EDIT: You can use DATA! It's quite pricey if you don't actually have a plan for it ); If you want data, you go to www.unlockit.co.nz on your iPhone via Safari. You then just tap continue, and tap "Custom APN" than you should see APN, Username, and password. Just skip down to where it says Carrier, and choose "US - AT&T" than tap "Create Profile" than just install it. WALA! You now have 3G/Edge data on your iPhone. GoPhones cost $20 at RadioShack. Alright, this is just a little tutorial on to have a GoPhone plan on any iPhone. No unlock needed, in order to get this to work on the iPhone 4 you have to cut the SIM card since iPhone 4 uses "Micro SIM" Well, I bought a GoPhone and activated it from RadioShack, thinking I can immediately take out the SIM and put it in my iPhone. I was wrong, I just kept on getting "No Service" at the top left corner. So I just dealt with my little $20 GoPhone for a week. Than I came across this YouTube video, that if you buy a new GoPhone it is actually locked to that specific phone for 6 months. So I thought maybe I could call AT&T and tell them that my screen broke in half (not sure if you have to say your phone is broken, or just say you bought a new phone and cannot use it. I just said I broke it to make sure.) and that I have bought a new phone but the SIM card just says "No Service". They asked no Questions and unlocked my SIM. I took it out and put it in my iPhone and.... WALLLA! It works. Unlimited Text/Calling $2 a day. It may not seem cheap, but some days I just don't use my phone.