Here are some good websites if you're looking for information on training, equipment, athletes, or a forum of people to chat with.
Beginner Triathlete - www.beginnertriathlete.com
Obviously geared towards the beginner triathlete, but I have many accomplished triathlete friends who love this website! They have a training log, race log (where you can write up race reports), forum, gear reviews, articles, routes and more! Good information!
SLOWTWITCH.COM - www.slowtwitch.com
Lots and lots and lots of articles! Good detailed information with articles seeming more for Ironman athletes/fans and total gear heads! Perhaps more for the experienced triathlete. Lots of articles on professional triathletes and pro races. I've found their forum very helpful when I'm looking into buying a particular product and want people's opinion on it. Also has sections on training, products, bike fit, and more.
trifuel - www.trifuel.com
I have not spent very much time on this site. But now that I look at it closer it looks pretty good! They focus on training articles and triathlon gear reviews. They also offer a forum, training plans, a training log and more.
Respond with a comment and let me know your opinions on these site and if there are any I missed!