there's plenty of great, interesting websites that promote veganism! I'm not vegan, but I've been looking into it!
One that's not (to me anyways) as "in your face" as Peta's is veganoutreach.org
Also, as far as diet and nutrition goes, try the Alternative Chicks forum at 3fatchicks.com
http://www.3fatchicks.com/forum/forumdisplay.php?f=121
It's a diet site, but they have a forum for vegetarians/vegans, and it's definetely helpful. They post all sorts of recipes, different ideas, and tips that will help you get in all the nutrition you need. Actually, whether or not your a vegan, this site is a GREAT site in general when it comes to information about healthy eating
Hope this helps some!