iCall to switch between VoIP, GSM calling on iPhone

Intersting development to allow iPhone owners to place VoIP calls over WiFi networks. It is callad icall.

It is developed as part of the iPhone Developer Program and will be available to all iPhone users.

Read more at:
http://arstechnica.com/journals/apple.ars/2008/06/30/icall-to-switch-between-voip-gsm-calling-on-iphone