By-the-way, I haven't seen mention of it with all this talk of verizon and sprint, but is no one aware that t-mobile has free international phone use in 125 foreign countries which includes mexico, all you have to do is ask them to add that plan to your phone for free, you've got free calls back to the US, free data (internet/email) and calls.
I had been hoping I'd get that on my T-mobile phone, but it apparently doesn't extend to their prepaid plans, or at least not to the $30 unlimited data and text plan I'm on.