Here’s a select list of my favorite technical writing resources. I use these all the time: Web Programming and Design

• HTML Entities, and URL encoder/decoder; HTML Entity Conversion Tool (i.e., for displaying XML code).
• Web browser user statistics; See Wikipedia’s background page describing data from more than one service.
• Web font statistics and Esperfonto font selection tool
• Free Online Font-Converter. For converting formats. See also font-forge.
• Google font directory. Tutorial on how to use them. Recommendations about suitable pairs of Google Fonts to use.
• CSS Media Queries Test page.
• Typekit font directory. Requires a subscription fee.
• HTML Color codes. List of Color Scheme Tools. Kuler color scheme picks, Combo Library (with URL Color grabber),  Color Pilgrim (Pallette directory, login required), ColourLovers; Intro to Color Schemes, HTML Color Chooser Tool and definition of color schemes. Vischeck, a way to check whether how your images and site appears to colorblind people.
• Web Accessibility Guidelines.
• Browser Statistics and Browser Display Dimensions
• CSS Examples and online testing tool and CSS-Discuss wiki. Also, a listing of browser support for new web standards and a listing of CSS support for mobile devices.
• Elements of Typographical Style applied to the web by Richard Rudder. Guided by Bringhurst’s principles.
• Embeddable Web Fonts Wiki and how to embed fonts. See also Fontsquirrel’s embeddable fonts which are free for commercial use and Kernest fonts (which seem to be web-embeddable; doublecheck). See also this thread and this guide to different kinds of embedding. This is mainly for web-embedding. See more about using fonts with ebooks below. League of Movable Type, a “hall of fame” for open source fonts.
• Interesting research about serif vs. san-serif fonts.
• Section 508 Compliance and W3 Web Accessibility Guidelines
• Tutorials: XSL, XML Schema, xpath

Tools

• Zamzar free file conversion wizard.
• Utilities: winmerge, Tortoise SVN, filezilla, putty
• Wordoff, a free online tool to clean up html code generated by MS Word.
•  Free online Jpg and png image optimization tools
• Snagit (online demos & online help), a $49 screen capture utility with extra features.
• Open Source Publishing: scribus, gimp, inkscape
• Freeware utility index
• Screencasting programs: Camstudio (Windows only), Wink
• Notetab Light, main text editor I use (Windows only).
• Windows Live Writer, a desktop xml-rpc friendly blog editor.
• Sigil ebook creator. Here’s the Sigil manual and a how-to on converting from MS Office/PDF/OpenOffice.
• Oxygen XML Editor. Full-featured commercial xml/xslt editor (with forums). See also XML Mind (also commercial) which is targeted towards documentation.

References

• Technical Forums: Stack Overflow,Pro Webmasters,Superuser,Doctype, Server Fault
• Subversion Book
• Typographic Design Patterns and Best Practices and 10 Useful Usability Findings and Guidelines. By Smashing Magazine.
• Better Font Stacks by Nathan Ford. See also codestyle’s font stack articleand Micheal Tuck’s article on the same topic.
• Organizing Content is a 15 part series by Tom Johnson about the challenges of information architecture and usability. Highly recommended.
• Oasis OpenDocument Ebook
• CSS Wiki and CSS Mailing list
• Technical Writing: Online TW Textbook and Managing Technical Writing online book
• Help-Authoring Matrix: Let’s you find the right documentation tool for the job. Note: software companies pay a fee to be listed here.
• Indoition has a good index of technical writing resources, including a review of Help Authoring Systems, Screencasting Tools and a Documentation Quality Checklist.
• Reference Cards: restructured text and an index of other cheat sheets.
• S5 Web presentation reference guide. Fascinating single-source solution for presentations.
• Klariti information re technical writing. They sell excellent-looking MS Word templates of assorted project/planning documents which technical writers usually have to submit to project managers.
• Agile Documentation, Scott Ambler’s summary of how documentation interacts with project management.

XML Flavors: Docbook and DITA

• Docbook Definitive Book, and Docbook XSL book
• Docbook-apps mailing list,
• Docbook HTML parameters reference (also the fo parameter reference).
• R.L. Hamilton’s article on DocBook vs. DITA
• DITA: 1.1 Specification, DITA XML Wiki, Ditaworld, DITA Users Mailing List, Dita for Publishers epub plugin,
• Docbook Publishers Schema: Specification, Mailing List, Info

XSLT Tutorials & References

• XSL: Copy with recursion template  examples. Good and accessible.  (Here are some more identity templates).
• Webeducator’s XSLT Tutorial is superb, probably the best I’ve seen.
• Stackoverflow’s questions regarding XSLT.
• XSLT Best Practices discussion on Stackoverflow.
• W3 XSLT reference (part of their mediocre tutorial).

Education & Technical Writing Weblogs/Portals

• I‘d Rather Be Writing is Tom Johnson’s cutting edge blog about documentation, blogging, wordpress and tech writing topics.
• UX MAtters is a academically-oriented usability blog
• elearningpost , an outstanding site with links to usability, information architecture and instructional design.
• Content Wrangler, a good news site on new technologies in documentation.
• Elearningcurve, a blog about instructional technology and technical writing
• I Came, I saw, I learned is Iconlogic’s blog with tutorials, reviews about technical writing products (Adobe, Camtasia, etc).
• User Advocacy, weblog by Houston technical writer Chris Borokowski
• Just Write Click is a blog by Austin technical writer Anne Gentle.
• I occasionally write posts about technical writing on my idiotprogrammer weblog.
• Creating Passionate Users by user advocate Kathy Sierra
• This is Broken (Good Experience) Weblog humorous weblog that illustrates usability and documentation problems by using real life examples.
• Oreilly XML Weblog, a series of articles written by O’Reilly authors.
• Jim Thoughtspot, XML Technology blog, with emphasis on DITA and technical writing.
• Boxes and Arrows, a leading site for information architecture and user interfaces. They have sections for Findability, Usability, and Learning from Others, plus a lot more. No RSS feeds for each section, but lots of articles added weekly.
• Open Office Training Weblog, full of tutorials and resources.
• TECHWR-L Forums, google group mirror of world’s largest mailing list for technical writers.
• Microsoft.public.word.docmanagement, a high traffic newsgroup for MS Word users.
• Daily Blog Tips & Weblog Tools Collection allow you to stay current about WP weblog technology

Houston/Texas Resources

• STC-Houston Forum
• Techblog, Dwight Silverman’s excellent technology blog for the Houston Chronicle. (I briefly wrote some guest articles for this blog).
• Idiotprogrammer Weblog. My personal weblog which covers a wide range of topics (not just technology). The weblog has a section specifically devoted to technical writing.
• Technical Writer Market & Salary Information: Texas TW Salary Information and  National TW Salary Data.

Epub & Ebooks Resources

• Oxygen XML: Oxygen-user mailing list; Latest user manual; video demos
• Epub Specifications: OPS, OPF
• Free & Budget Epub creation tools: Jutoh, Calibre (User Guide), Atlantis, (blog), Writer2epub (with English forum), (Export from Open Office),
• Epub Zen Garden
• Kindle formatting guide, Kindle Previewer tool and KDP community
• Pressbooks, a wordpress cms for outputting epub files.
• Epub Resources (collected by Keith Fahlgren); Epubcheck tool (and online version)
• Blogs: Threepress Epub blog, Epub books blog, Tools of Change, Pigs, Gourds & Wikis ; Epubsecrets
• Formatting poetry for kindle and for epub
• MobileRead epub forum and Calibre ebook conversion software;
• Mobileread eproduction wiki for ebooks.
• list of ipad’s ebook reader apps (June 2010)
• Mobipocket Guide: HTML Reference, Formatting Suggestions and Formatting Forum.
• My technical braindump about ebooks and epub

Podcasts

• SXSW Podcast, lots of podcasts from SXSW conference, with many topics of interest to technical writers.
• IT Conversations, a leading portal for podcasts on new technologies (especially web technologies).

Book Production

• a free download to people making print books on Createspace (with generally useful information). Also, Smashword Style Guide.
• Mobileread list of free and commercial ebook sellers.
• Fonts for use with ebooks: Howto Embed fonts in ebooks by Liza Daly (Sept 2009). Free Unicode Font Faces. For commercial use in epub files, they need to be OFL ,(more here), GPL with Font Exception or Public Domain. Open Font Library contains OFL fonts; not a lot though. Smashing Mag also has a regular column of free high quality fonts: here, here, here, here, here, here, here, here and here. These fonts, though nice-looking, may have restrictions; read the fine print.
• Nexus Font Manager, a free tool for viewing and comparing fonts. (here’s a long review of several others). Fount Identifier, a browser bookmarklet which lets you identify all kinds of embedded fonts.
• Fonts currently on Ipad/iOS.
• Stanza FAQ
• discussion about using wordpress for book publishing
• Guide to Comparing Ebook Distribution Channels/Services for Ipad (Sept 2010). (PDF). 10 page reference guide describes requirements, royalties, formats. Highly recommended.
• epubcheck error reference.