You need to get it unlocked at your local phone store it costs about $25
You can also search for your cellphones unlock code and go to mobileunlock.co.uk. It will ask you for your phones IMEI number and walk you through the steps. But I think the charge like $15.samsung tmobile phone how to put in a unicel sim card?
but it has been used beforeHow do I insert the sim card for a nokia 2330?
If you unlock the T-Mobile Blackberry, You can not only use AT&T SIM but you can use any international GSM SIM to it. You can unlock your mobile using unlock code. You can get the unlocking code from Theunlockarena.com at affordable cost.Do they sell prepaid Sim cards for Sidekicks?