Anyone using a prepaid SIM on an unlocked GSM iPhone?

[rgG]

I would recommend either StraightTalk or H2O. You do not have to unlock your iPhone to use it on either of these. Both are AT&T MNVOS. MMS will required some work, if that matters to you, but pics through iMessage work fine. As said, no visual voicemail. My daughter has had her iPhone, not unlocked or jailbroken, on H2O for over a year. Both ST and H2O have different plans, so you can just pick the one that fits your needs for amounts of minutes, texts, and data.