In my experience, buying a SIM card is not a problem, they're everywhere.

The only thing you'll need to worry about is if your phone is "locked" most GSM phones you buy in the States are locked to only work on the network authorized by the company you bought it from.

I have an unlcoked tri-band that works everywhere I've been with any SIM, but unless you know that yours is, I would ask someone (like the guy's personal SIM in the phone card shop for example)...anyone really.. to slip their SIM into your phone and see if it finds the network before spending the 20 squids on your own.

Also, take a look now to see if your phonebook is being saved on your sim or on the phone memory. If it's on the sim, jot down those you need before switching..

good luck.


Editing to add: I just read another post about ATT using GSM 850 in N. America, so it seems my TRI-Band phone will no longer be enough...time to get a QUAD-band!