Im seriously considering changing to T-Mobile and am looking at their plans.. does anyone know, is it possible to change plans "midstream".. though I'm guessing without a contract, there is no stream. Anyway, lets say I sign up for the 2.5 gb plan and find I really want unlimited.. can I just change my plan online any time? Can I change back the next month after I do that? Also, is tethering included in their plans, or is that a separate charge? Thanks.