Neville Ray, T-Mobile’s CTO, just announced , not only T-Mobile USA will launch the new iPhone sometime this year, maybe in 3 months, but also said, that T-Mobile hosts almost 2 million unlocked iPhones running on 3G already in a few places where T-Mobile has deployed 1900 HSPA+ network like Denver, Los Angeles, San Diego, Virginia and Las Vegas.
Raid also said that 100.000 more unlocked iPhones are coming to T-Mobile too. Those iPhones comes from AT&T mostly.
Now with the new HD Voice service, some iPhone users can take advantage of that. The current iPhone 5 supports AMR-WB, the HD Voice codec T-Mobile uses.