I'm starting to hack up my copy of MediaWiki, and I'm documenting my adventures. I hope this will be useful to other programmers who are trying to learn come to grips with web programming.
http://wise-nano.org/w/Programming_notes
I'd appreciate review and/or help writing the sections on the various programming languages and systems. It's under GFDL, so could become MediaWiki material when it grows up. For now, I've linked to it from a couple of appropriate MediaWiki help pages.
Chris