VoIP Comes to the iPhone via Fring
I don't know what's happening with Apple, but the iPhone creator has just approved a VoIP application for the handset. Fring is available from the iTunes store for free now and you can use it for free, unlimited calls. Sure you're going to pay for your data but I'd install it for all those times when a free WiFi spot is accessible. Better get it now too since you'll never know when Apple changes its mind about the whole VoIP thing.
Here's what Fring says:
You will have one searchable contact list with all your instant messaging buddies from Skype, MSN Messenger, Google Talk, ICQ, Twitter, Yahoo! and AIM, so you can easily see whose available and where they can be reached before dialing or starting a live chat session.