UPDATE: Oct 25 2013
As part of a recent carrier update, also included with iOS 7.0.3, the network name in your status bar will show TFW instead of HOME. So anywhere you see HOME in the text or screenshots in this guide know remember that TFW is acceptable and expected.
I’ll assume you have:
1. Purchased and activated a StraightTalk AT&T or TMobile network SIM.
2. The SIM card is in your iPhone.
3. You are able to make and receive phone calls
4. you can send and receive SMS / Text Messages
The problem you are trying to fix is.
1. You cannot use data or internet
2. you cannot send & receive MMS picture messages
3. you cannot use data or send & receive MMS
If you are using the Straight Talk TMobile network SIM card, the guide should still work for you. A number of readers with Straight Talk TMobile SIM cards report problems. Some get data and mms to work with additional help, others need to follow up with Straight Talk technical support. Continue with the guide, and leave a comment if you have a problem, I will try to help you.