I'm looking on the T-Mobile website and see a plan for $15 a month pre-paid. One of the phone options is to just buy a "T-Mobile® Prepaid SIM Card Activation Kit" that is "ready for your GSM device." Does this mean that I can use the SIM card with any phone that is GSM? Or can I use it with any phone that takes a SIM card? Or are there limited phones I can choose from? I don't know a lot about SIM cards or anything like that, and I am a new T-Mobile customer (currently with Virgin Mobile). Also, can you give a list of GSM or SIM card phones? (Specify which, please).