Peter Hamm , Dec 19, 2008; 07:40 a.m.
You should go to the wedding forum and search on this topic, you'll probably find lots of discussion.
You'll get a lot of recommendations for the excellent 17-55 f2.8. That and a decent flash like the SB600 or SB900 will be great. (Yes I know you probably can't shoot with flash inside the church, but you'll want it for the formal photos. For that, depending on how big you're printing and such, you may be okay with the kit lens.