I've recently written a few biodiesel-oriented diaries, and the number of questions I've received has convinced me to put a biodiesel resource list here. I would urge anyone who feels comfortable with the dKosopedia to turn this information into an entry there, if possible. Thank you.
Journey to forever- excellent biofuels library (LOTS of info, especially for homebrewers)
http://www.journeytoforever.org/biofuel_library.html
Biodiesel Infopop Forum- great, vast worldwide forum for homebrewers
http://biodiesel.infopop.cc/6/ubb.x?a=cfrm&s=447609751
Biodiesel Now!- more excellent forums, but not really about homebrewing. General biodiesel banter.
http://www.biodieselnow.com
Fred's TDi Club- a huge site for VW TDi drivers, it has a great little biodiesel section
http://forums.tdiclub.com/postlist.php?Cat=&Board=UBB44
the National Biodiesel Board- you'd think this would be the best site of the bunch. Certainly very official, but some people feel it represents the soy and petroleum lobbies more than biodiesel, as it has a tendency to focus on soy B20 (a blend with 80% biodiesel). Still a good site, with great resources, including maps of where biodiesel is in your area.
http://www.biodiesel.org
the Biodiesel Council of California- a group of sustainability-minded biodiesel proponents working at creating a lobby reflective of their concerns. Stay tuned to this one.
http://www.biodieselcouncil.org
the Yokayo Biofuels website- I have to include my own company's website, simply because it is a good resource, especially the history sections (history of biofuels, history of diesel)
http://www.ybiofuels.org
There are more, obviously. Right now, though, I gotta get back to work. If you think something should be added, feel free to make a comment. Thanks.