fring is a mobile internet community and communication service that allows friends to connect, share experiences and enhance their communities (Skype , MSN Messenger, Google Talk, ICQ, SIP, Twitter, Yahoo! , AIM ) together, using your iPod & iPhone's internet capability.
Share experiences and stay connected with friends in real time using all your favorite online communities and communication tools-Enjoy voice calls (VoIP) over WiFi, stay connected with your online world with instant messaging from anywhere using fring multiple connections (3G, WiFi, GPRS , Edge) & launch new experiences directly from your contact list.
• VoIP Calls over WiFi
• Instant Messaging
• Integrated dynamic contact list with real-time contact availability
• SIP integration
• Multiple Connection types
• Push notification support for fring, Skype, MSN Messenger, Google Talk , ICQ, SIP, Twitter, Yahoo! , AIM communities
Fringe is the first 3rd party application "Download" by using the installer, which may have messenger (most - see title) and especially skype. "Especially" for skype that besides the fact that writing, and you can call anywhere in the world free or much cheaper. Yes, it is VOIP for iPhone and first impressions are positive.
for instance in Fringe iPhone must add Susa: http://fring.com/iphone.xml