As far as I know, international roaming is all about convenience and not about price. If you're paying for your own phone calls abroad, get your phone unlocked and buy a prepaid sim card. I have had a GSM phone and was a loyal SIM card avocate since AT&T rolled them out, but I recently switched to sprint, as the A900 with their "sero" plan was a far better deal than anything out there. Of course, shortly after they switched they disabled "tethering" for their EVDO phones, but that always happens as soon as I start using a carrier. (well, T-Mobile is the only precedent for this, but they did the exact same thing). EVDO is amazing, certainly worth giving up GSM and cingular's edge service. Of course, I live in an area where I could get UMTS at&cingular service, but the two phones they'd make you buy are overpriced and massive..

I guess the point of all the above is that unless you need to have the same number work abroad or unless you travel internationally every month, chose the US Carrier of your choice and buy an unlocked quad band GSM phone to use when you travel if you have to.

Matthew