Tim Haines, the developer of the excellent BurnBall game, has started a list of iPhone developers who use Twitter. The last time I checked, there were over 100 iPhone devs on the list. If you have a Twitter account, go add yourself to the list. There is no minimum requirement and no test will be administered, it's just an informal list of people interested in iPhone development who also use Twitter.
D'oh, it helps if I include the link, doesn't it?