any GSM sim card will fit in any GSM phone.
yours will fit in another T-Mobile and work with no issue.
yours will fit in an AT&T/Cingular phone, but the phone will have to be unlocked to use it.
any GSM sim card will fit in any GSM phone.
yours will fit in another T-Mobile and work with no issue.
yours will fit in an AT&T/Cingular phone, but the phone will have to be unlocked to use it.