[jonknee]

There are multiple kinds of devices. Femtocell is basically a little cell tower that is in your home/business. UMA is when you can do voice over WiFi and it was backed by T-Mobile, but they have shied away from it and not introduced it with Android. It's somewhat tricky and needs phone support (for the handoffs between networks), whereas any phone can support femtocell.

[drzaiusapelord]

Voice over WIFI is doable with Android. The latest update to my Vibrant installed the feature.

[jonknee]

Good to see, I had missed that T-Mobile made the UMA move on Android. Does it do the seamless handoffs or do have to make a call either over the cellular network or WiFi?