Everyone wants a piece of Skype
Taiwanese manufactures were playing up to Skype users at Computex 2005, showing off their SKype (or just general VOIP) handsets
designed to make Skype easier to use and more cell-phone like. Some have built in WiFi that will automatically detect a WiFi zone and enable you to make calls. I think the device would need to be able to function as a regular cell phone and a VOIP phone interchangably so you don't need one phone for the WiFi and one to use when you're not near a WiFi connection.