AT&T Locked iPhone 3g, 3gs & 4 with Straight Talk Sim Card program
Setting up your your new or used AT&T locked iPhone is relatively easy. Remember to select the AT&T compatible Sim card when purchasing from the Straight Talk web page. The iPhone 3g and 3gs will require a standard Straight Talk Sim card, also known as a mini Sim. The iPhone 4 and 4s will require a Straight Talk micro Sim . Be aware that you will not have MMS (picture, video, music texting) unless you jailbreak the phone. There is no way to get around that. You will, however, be able to make/receive phone calls as well as use data services including web, iTunes, Netflix, etc. So lets get started! Find used iPhone 3g, 3gs, 4
1. Activate your new sim card on the Straight Talk web page. Though you have only a Straight Talk sim card and not a phone, you will still activate it as if it were a phone. Select the Activate/Reactivate link. Next you will select whether you are activating a new number or if you are porting an existing phone number. You will now be prompted for the Serial Number. This will be the Serial Number of the Sim card not the phone! Your Straight Talk Sim card kit will come with a red card with the Sim Card serial number. Finish up the activation by following the prompts.
2. Once your Straight Talk sim card is activated, install it on your new Straight Talk to be iPhone. Find a paper clip and bend it as shown on the image below. Unlock the Sim card tray from your iPhone. iPhone 3g and 3gs have the tray on top, iPhone 4 and 4s have the tray on the side. Stick the bent paper clip into the small hole on the tray. See below:
iPHone 3g/3gs Sim Tray
iPHone 4 Sim Tray
3. If your phone is new to you, reset it to clear all data and settings if it has not been done already. You will know if it has because it will tell you to connect to iTunes and will only allow Emergency calls. Install iTunes if you haven't already, connect the phone to your computer and follow the onscreen instructions to sync to iTunes. Continue to next step if you've already done this or if this already your phone and you don't want to clear all your stuff. In case you don't know how to reset your iPhone, it is done from Settings->General->Reset->Erase All Content and Settings.
4. You will see HOME, signal bars and 3g (if you are in a 3g area) on the top left corner once your Straight Talk Sim card is active.
5. At this point, you can make and receive calls as well as send regular text messages. Your data will not be working at this point, however. Your Straight Talk Sim card activation kit will have instructions on data setup but you will not be able perform them on an AT&T locked iPhone. The Network settings screen is not available on such phones. Continue with the steps below to activate data.
6. You will need to have WiFi access to continue to activate your Data. Turn on WiFi and connect. If you do not have WiFi or prefer to set up your 3g Data using Apple's iPhone Config Utility, use this APN Set up Tutorial instead.
7. With your iPhone's WiFi connected, open up Safari on your iPhone and visit http://unlockit.co.nz.
8. Scroll to the bottom of the page and select Continue, then select Custom APN.
9. Select the country, then select Straight Talk for the Carrier. Select Create Profile to install the Straight Talk APN settings.
10. Reboot by turning phone off/on then test data by opening up Safari and visiting a website. Congratulations, your phone now has data and is active with Straight Talk. Again, if you want MMS working, you will need to jailbreak your phone to get access to the Carrier Settings screen to set MMS settings. If you don't want to go through the hassle, simply set up an Email address and send pictures, videos, music etc using the email client.