SIM compatibility information
From HowardForums Wiki
T-Mobile SIMs whether for use with prepaid service or used on monthly billed accounts are identical. The difference is only in how billing is accomplished with prepaid requiring that you pay for your calling time in advance and with postpaid billing a statement is either mailed to you each month or your charges are available on line. You may use a SIM configured for prepaid or monthly in any handset that is either locked to T-Mobile or is unlocked.
You can also use a T-Mobile SIM in any frequency compatible (1900 Mhz minimum capability)handset provided that the handset does not have any SIM lock restriction from another network.
Source(s): SIM compatibility information