A lighting link-farm -- many of these are themselves nests of more pointers.

*Note: a lot of this is out of date and probably has several dead links.
I haven't had a chance to go back through and recheck everything, but there's always your nearest search engine once you have an idea of what you're looking for.

http://techno-fandom.org/~hobbit/lighting/lighting-linkfarm.html
That's THIS file -- for easy single-point access

Useful lighting / production info

http://theater.harvard.edu/jobs/crew/electrician.html
Excellent description of a theater electrician's job. The whole Harvard theater site is really good, albeit tailored for their specific spaces.

http://theatre.harvard.edu/jobs/ld/quick.html
More from the Harvard folks

http://www.mts.net/~william5/sld/sld-toc.htm
An extensive "Lighting Design 101" set of documents

http://www.d.umn.edu/~mharvey/th1501a-z.html
Nice description of the design process. Also look at "classindex.html"

http://www.d.umn.edu/~mharvey/websitelighting.html
Many good pointers in general

http://www.northern.edu/wild/th241/ldw02.htm
http://www.northern.edu/wild/th241/th241.htm
http://www.northern.edu/wild/th241/ldw03.htm
Larry Wild's theatre courses and other info. There's a *ton* of stuff here

http://www.northern.edu/wild/jressay.htm
Larry Wild's recreation of Jean Rosenthal's "photo essay" on directionality

http://www.vincentlighting.com/glossary.shtml
One of many glossaries out there. Google some of the terms for many more

http://www.people.virginia.edu/~rlk3p/classes/usem171/Glossary/Terms.html
Rock-n-roll terminology

http://techno-fandom.org/~hobbit/flipcoil/howto.html
How to properly over/under coil up cables

http://www.dmx512-online.com
Good rundown on DMX by Ujjal Kar

http://www.prosoundweb.com/lighting/articles01/dalelee/dmx.shtml
DMX protocol description

http://www.hollywoodlights.com/production/techtips.htm
General theater tips and info

http://techno-fandom.org/~hobbit/lighting/arisia11/pony/
How to adapt artwork and hand-cut a gobo from pie-plate aluminum -- somewhat tedious but quite effective

Forums

[There are probably many others besides lightnetwork, too...]

http://lightnetwork.com/
The Light Network forum -- very active, very professional. Site wants cookies enabled to work right.

http://techno-fandom.org/mailing.html
Instructions for joining the techno-fandom list. This is a loose collection of volunteers, mostly from the northeast corridor but with a few members scattered around other areas of the country, who periodically gather at SF conventions, folk festivals, and other events to do production tech for fun and useful experience