Yes it is possible and it is true some of the PST stuff i use has support for this, and no they would not have to have GSM, a RUIM is a pretty like a SIM card or on a CDMA network its the ESN, just take it out and pop it out into another RUIM phone which im pretty sure its not as easy as that but maybe it is, never the less if cricket went to that system that would be kick *** and now that i think about it yeah they would have to put up GSM towers as well they dont have to but if we wanted to use a GSM phone on cricket then yeah we would and a lot of the CDMA nokia phones come like that. If anyone knows where we can get a RUIM phone that be cool i want to test one / just get a feel for one