Eschewing the femtocells that most of its competitors have embraced, T-Mobile USA has long touted WiFi calling as the answer for augmenting its cellular network -- problem is, they've generally done a poor job of rolling it out to a wide variety of handsets. Notably absent from the compatibility list so far, Android is finally being welcomed to the club today -- as rumored -- with the recently-announced myTouch and Motorola Defy among the first models to nab the feature. Though availability on currently-sold phones hasn't been announced, T-Mobile does say that WiFi calling is "anticipated to be available on a growing selection of T-Mobile's Android-powered smartphones in the coming months," so we'll go on record hoping we see a few upgrades in the works (G2, we're looking straight at you).