hi, i'm interested in purchasing the iphone 3Gs 32gb, but i'm not sure bout some things.

first of all, when they say domestic calls do they mean maxis to maxis? or what??

also, is it possible to change from example, ivalue plan1 to plan2 or plan2 to plan1?

lastly, i see that digi is also coming up with their own iphone package, can anyone tell me which is better? i know the digi package is not out yet, but it will be soon..i don't really need the 3g data plan, because i intend to use it with wifi most of the time..