I'm travelling to the U.S. and want to have cell-phone connectivity there. International roaming is out-of-the-question expensive.What do people recommend? Are there any services that give pre-paid SIM cards?I basically want people back here to be able to call me, and to occasionally make calls domestically in the U.S. such as when co-ordinating plans with someone. Will hardly use SMS probably, but if I can get access to EDGE internet that would be awesome!Any suggestions?(alternatively any suggestions as to good phone cards there?)