Along with active.com, these two should get you squared away.

http://www.trifind.com

http://www.usatriathlon.org - on this site I think you need to follow the links for Athlete Info and then Event Calendar

Are you going to do a Sprint? I suggest doing a USAT race for your first one if possible. They do a good job of educating you on all of the rules and keeping the course (especially the bike) safe.

Good Luck!