Remove the SIM card and restore it with iTunes. Just do what iTunes tells you to do, it won't mess up any plans. It will go all the way to activation and then say it can't. When you disconnect from iTunes it should allow you to use it like an iPod Touch and just say "No SIM" where the signal strength would normally be shown.
I did exactly as you said, and when I disconnected from iTunes, it has the icons for me to connect to iTunes, and says, No SIM card installed, insert a valid sim....etc... When I open (slide the arrow), I get the phone pad "emergency only"......
I just want to get this so the kid can use it again ..... any other suggestions?
I appreciate your help, by the way.