can you use a t-mobile phone with a cingular sims card?

[hanhdonna]

i have att, and i want a new phone. but my 2 years arent over yet and im too cheap to buy a new one and i noticed that T-mobile has nicer phones anyways, but theyre company sucks, and i want to stick with att

[jocoolguy]

You can Buy T-mobile phones and to use Cingular/AT&T network you need to unlock it.Visit the site Classicunlocking.com get the unlock code for T-mobile network locked phones and unlock it easily.Then use with other GSM Network sim card.Without unlocking you cannot use other GSM Network sim card.