AT&T uses a different frequency band for 3g (1900 MHZ), T-Mobile uses the 1700 MHZ band for their 3G. Thus, there is no Blackberry for T-Mobile upcoming unless there is a variant in the works for the separate band of 3G for the Bold, or if AT&T gives up on the Javelin and passes the blackberry torch to T-Mobile. I hear that the latter is probable due to the refusal by AT&T to release any new 2G devices that use data.