I was getting really terrible 3G service on the iphone. I got the phone on day 1 and paid for the data plan for 2 months. I wanted to get rid of the Data plan as I was not using the data plan on the 3G network but was paying for it. So I took the following steps to get the data plan off the Iphone 1. You'll need another phone besides the iphone. 2. Take the SIM from the IPHONE 3G and put it in the extra phone you have. 3. Call ATT from that extra phone with you Iphone 3g SIM in it. 4. Tell them that you were unhappy with the service and that now since its been more than 30 days You can't return the phone so you sold it to someone but kept your sim card. (They can tell if your calling from Iphone) 5. Now that you don't have the Iphone you would like to take the data plan off. 6. They'll take off the data plan and the visual voice mail since both are built in together. you can still use the other method to retrive your voicemails. 7. Also they asked me for the IMEI of the other phone (phone your calling from) but I decided not to give it to them but telling them that if you take the battery out you'll get disconnected and when they tell you to type somestuff to make it come up on the phone tell them that nothing comes up since we have an active call. SO DO NOT GIVE the IMEI of the phone you are using. (I don't know what that will do but I did not want to give it to them) If anyone does give if please post if you Iphone still works. 8. Also make sure you tell them to block all data to your phone. (Since people want to check out the iphone they usually assume you have data plan and start safari and so you'll get charged pay per use.) 9. Once this is done and the rep confirms that the data plan has been removed and block on data has been put on hang up. 10. Now remove the SIM from the phone you were talking on and put it back in your iphone. P.S the GPS signal still works. Only the Map doesn't show. So if someone ever develops and app with Maps on your iphone then you're good to go. I've been using my phone on wifi everywhere in philly. I'm happy that I have a iphone 3g and I don't have to pay the $30.