I am in the same situation. My wife went from a Curve to an iPhone. We tried Google Talk and there is not a separate app for the iPhone so that was out. We tried AIM and it worked well for a few days. I then found out that while it would say I was logged in on my Bold I really wasn't. She would send me a message and it was telling her I was not logged in. The 3rd attempt was Yahoo Messenger, which has worked great for the past 2-3 weeks. The smileys are a lot better on Yahoo, too.