how come sometimes, when i'm going out of town, it'll change from saying EDGE in the corner to (i think) GSRM and CDMC or something along those lines? does that charge me extra? why does it change?
It is either roaming or just in a poor signal area. t-mobile does not charge for roaming so you have nothing to worry about, other than slow or nonexistent data connection
it would be EDGE, edge, GPRS, gprs or GSM on your TMo device... and no it is not extra. Some areas have better coverage than others, those are different connection types
