Enable iPhone 4 FaceTime on T-Mobile and other Unofficial Carrier Worldwide
But now, you can activate FaceTime feature on iPhone 4 operating on T-Mobile or other unofficial carriers worldwide
http://www.gadgetsdna.com/how-to-enable-iphone-4-facetime-on-tmobile-unofficial-carriers/5660/

But now, you can activate FaceTime feature on iPhone 4 operating on T-Mobile or other unofficial carriers worldwide
http://www.gadgetsdna.com/how-to-enable-iphone-4-facetime-on-tmobile-unofficial-carriers/5660/
I got a factory unlocked iPhone 4 from the UK. I live in the U.S. and use a small GSM provider in my area called Cellular One. When trying to activate FaceTime, I was stuck on the "Waiting for activation" screen.
I finally called 1-888-FaceTime and was told that FaceTime won't work on any non-supported networks, like T-Mobile, etc. It appears that even though the phones are sold factory unlocked, FaceTime requires a specific server on the network (like visual voicemail) so it won't work on any other network.
That is disappointing. I hope that Skype begins to use the video calling feature.