I came across O2 (Oxygen) Wireless yesterday. Their gimic is that you can call 50ish countries (only landlines…of course) for nothing but normal airtime minutes. Their rates are kind of steep (14 cents as opposed to 10 cents from ATT) but, if you do international calling, it looks like a nice alternative to calling cards. From their coverage map, it looks like they piggyback off another cell company…I’m not sure who though.
I also found out that you can buy their SIM cards–so we know it is some GSM provider–at Best Buy.