Mobissimo

If you're a frequent traveler, you know while mobile phones have made communication much easier, calling to/from a foreign country is not that easy. Trust me, ever try to make a phone call from Brasil to Argentina with an American phone? A little more here:

Cingular Wireless is often cited by readers as the best domestic service for enabling your cellphone to work internationally, though not necessarily the best for domestic service. Verizon, often cited as the best cellphone service domestically, is also often cited as among the worst for enabling your cellphone to work abroad.

There you have it. I have two phones, one for the US and one for abroad so I can switch out the SIM card, read the rest of the article to find out what may be your best solution.