Can I use a T-Mobile SIM card with a Cingular cell phone?
Hi no you can;t use t-mobile sim card in phone locked to cingular network until you unlock it …If you are in need to unlock your phone from cingular network then have a look at sites like Simpleunlocking.com here they render unlock code for all mobile models ..After purchasing the code from them visit sites like Mobileunlockguide.com who render free instruction guide about how to input code in your mobile to unlock it ..After successfully unlocking your phone you can freely use it with any GSM sim ..