I just did my first IDPA shoot in Topeka, KS. (shot my P220) It is run and attended by some really good people. It is held at Kaw Valley Gun Club (an indoor only range - kvgc.com) The name of the club that puts on the IDPA shoot is "Double Tap Defensive Shooting Club"
http://www.freetrapper.com/doubletap/index.htm

It was tons of fun. I learned a lot. The guys who have been doing it a while were more than happy to offer tips and advice. Hopefully after doing it a few more times I'll get more relaxed and my scores will get better. They put us through some very dynamic, practical, real life scenarios.