switch to t-mobile w/o contract?

I am on Cingular now and I wonder if I can switch to t-mobile without a contract.....I mean already I have a phone and can I just get a sim and switch to T-mobile without any contract

[Crossblade]

prepaid card

[nimaeve]

You can only switch without a contract if you obtain prepaid service. If you sign up as a post paid customer, you will need to take at least a 1 year contract. That is a NON-negotiable.

Also, the warranty for your Cingular handset will NOT be honored by T-Mobile, nor can you purchase T-Mobile's handset insurance on a non-T-Mobile branded cell phone. Be aware that many of the functions of your handset may not work the same on T-Mobile's system. You can preview T-Mobile's contract on their website. Good idea to read it before you sign up.