Fring is an app for the iPhone and iPod Touch that allows you to not only connect with your friends over several different instant messaging services, but it also offers the ability to do VoIP calling. The functions of this app are pretty average overall, but the addition of a VoIP feature into an iPhone app are what got it the attention that it has been receiving.
With Fring, you can connect to your Skype, MSN, Google Talk, ICQ, Twitter, and AIM accounts. The unfortunate thing is, adding your account is the only customization you can accomplish with those services through Fring. You won't be able to sort your buddy list by account, nor will you be able to add a contact to any of your buddy lists. The only contacts you can add to Fring directly are Fring user contacts through their phone number or Fring ID.
The chat functionality is pretty basic for an instant messaging app. You can't turn it in landscape mode or anything, unfortunately. You can make outgoing SIP or VoIP calls when connected to WiFi to other users with that functionality. When testing out this app we had nothing but issues with trying to get incoming or outgoing calls working. We attempted both landline and client to client calls and none of them worked. Unfortunately, the best we could do was call the test line and our recorded voice played back sounded awful.
Fring has a really cool look to it and could easily beat out an app live BeejiveIM if it incorporated more basic instant messaging features, cleaned up the VoIP and SIP calls, and allowed for a landscape mode for typing. Until that happens, this isn't an app you'll be keeping on your iPhone for very long.