OK, really, before the smart remarks... I just bought a 3GS to try out ATT service in my area. I am currently with Sprint and have 3 other family members that are on my plan. None of our phones can call my iPhone. We get an funny message that says "the number or code you dialed is incorrect, please check it and try again". Then it says code 5 and some other 3 digits. But, any other line - landline, Skype, my office answering service/forwarding - seems to get through. And I have no problems calling or texting the Sprint phones - and the number comes through just fine on caller ID. Since I have not ported my number yet, I could still get another number or just go ahead and port. But I have never seen or heard of such a problem. Was Sprint looking over my shoulder??