Same thing happened to me. I mean, to my phone. If I search for a network, I get a error message. Tried with T-Mobile SIM card (US), Claro SIM Card (Brazil), TIM SIM Card (Brazil) and BrasilTelecom SIM Card (Brazil). Nothing happens at all, the network signal meter shows a X over the bars, like if there's no signal, no network available.
I can't even register APNs on the phone, it rejects the new one after saving it. I mean, I enter all the data but when I come back to check there's no APN registered on the phone.
When I try to use that Wireless Call, a T-Mobile app, it says the SIM is invalid, so I guess that all SIMs are being rejected by the phone, all the SIMs are "invalid".
Hope you genius can help us out here. It's not nice to have a phone but use this nice piece of hardware as a *%&#*'n iPod Touch. That's just breaking my heart (also my pocket's heart)