Rom Feria over on Tech Without Wires finds an interesting application for the iPhone by a company called
A company called iCall. He describes it as similar to the TMobile's Hotspot@Home service. Features include:

• Make and receive calls over WiFi
• Transfer inbound calls from a regular cell call to WiFi instantly and seamlessly - save your expensive minutes
• Access your same address book
• Customize your voicemail options

Here's a video clip of the application in action:


iCall VoIP on the Apple iPhone from Arlo & Andy on Vimeo.

What's cool is that this is not going to be an application for jailbroken iPhones. It uses the Apple's standard SDK. Of course, right now, the application is not available to mere mortals, but it is an interesting demonstration none the less.

I suspect the folks at Truphone are also working on something similar, though I have no word from them. Perhaps they'll comment on this blog post? :)