I'm considering getting a 3G3 on AT&T. The basic plan does not cover international use. With my old dumb quad band phone, I could drop in a pre-paid SIM whenever I went abroad and get full use on GSM networks. But of course, voice only. No data. What happens with an iP 3GS? Is there any way to get the equivalent of EDGE or 3G when abroad using another SIM card? Would wifi in central Europe, Russia, etc work? Does AT&T provide any sort of strategy for dealing with international use? Thanks.