settings - about phone - phone identity
and you don't need to provide an imei to activate prepaid. you can enter all 9's if using the website or activate by phone and say you don't have one to give
are you sure the phone has aws? according to the wikipedia, only the tmobile version has that band. it'd be pretty lousy to use that phone with edge only. if it doesn't have aws, i'd consider straight talk's unlimted $45 plan. they offer both tmobile and att so make sure you get att.
not sure why *#06# doesn't work and there's no sticker behind the battery. maybe see if you can flash a worldwide or us rom.
South Korean variants
All of South Korean variants have a T-DMB tuner in place of FM radio tuner. They also have Samsung's Korean input system for feature phones as well as Dubeolsik layout in their virtual keyboard.
SK Telecom's Galaxy S II (SHW-M250S)
The SK Telecom variant uses SK-MMS system instead of OMA-MMS system for MMS. Additional features for SK Telecom users are installed by default.
KT's Galaxy S II (SHW-M250K)
This variant uses KT's Wi-Fi CM[clarification needed] instead of Android's Wi-Fi CM to connect Wi-Fi. Additional features for KT users are installed by default.
LG U+'s Galaxy S II (SHW-M250L)
Because of mobile networks LG U+ have, it uses EV-DO Rev.B (KPCS 1.8 GHz) instead of WCDMA and HSPA. It is slightly thicker (9.4mm) than SK Telecom and KT variants (8.89mm). Additional features for LG U+ users are installed by default.