Want to turn an iPhone 4 into a pay go phone? David chimed in on our past prepaid iPhone article to describe how he got his iPhone 4 setup with a pay-go plan by transferring sim cards with AT&T. This method works to get pay-go calling and data use!

How to setup an iPhone 4 as a Pay-Go phone

Note: this applies to the AT&T iPhone 4 model only:

Be sure you have an existing pre-paid phone with an existing pay-go sim card

Get an iPhone 4 off contract with a micro sim (FYI: you can buy iPhone 4 without contract directly from AT&T or Apple, but it’s expensive)

Call AT&T at 1-800-331-0500 and say “Customer Service” to talk to a service representative

Request assistance in transferring your old pay-go plan to a new sim card

Provide the old pay-go sim card ICCID number and the new micro sim ICCID (from the new iPhone 4 About Screen or iTunes)

Provide your iPhone IMEI number, printed on the microsim caddy or from the iPhone About screen

AT&T will recognize from the IMEI and ICCID that this is an iPhone 4, they will say that while they can do the transfer you will not be able to use the internet (read on for enabling data). Agree to this, and get the pay-go line transferred to your new micro sim

Now connect the iPhone 4 to iTunes to activate the phone, once activated you will be able to make phone calls on a pay-go basis

You may need to restart the iPhone once to get calls to work, but activation is usually immediate after speaking with AT&T customer service.

Now that you have the pay-go calling part taken care of, you can get data working too by installing a custom APN.

Note: Some users say this requires a jailbreak and others have been able to get it working without one, here’s how to jailbreak iOS 4.2.1 with Greenpois0n RC if you require a jailbreak.

How to Enable Data & Internet on a Pay-Go iPhone 4

Again, this applies to the AT&T (GSM) iPhone 4:

Jailbreak the newly activated iPhone 4

Connect your iPhone 4 to a WiFi network so that you can access the web

From the iPhone 4, open Safari and visit http://unlockit.co.nz and tap “Continue”

Choose “Custom APN” and select AT&T as your carrier

Tap on “Create Profile” to download and install the new custom APN

Once you get a “Profile Installed” message, your custom APN profile will be working. Now restart the iPhone 4 and try using your data plan, it should work perfectly. You may want to temporarily disable WiFi on the iPhone to be sure that your are using the data network and not WiFi while you test this.

Don’t have an iPhone 4? No problem, setup an iPhone 3G or 3GS as a pre-paid iPhone, it’s even easier since you can just swap sim cards directly!

Thanks for the iPhone 4 instructions, David!