I have a Cingular cellphone. It is a Motorola V60i. I know from checking the frequency used in Spain (900/1800) that my cellphone can be set to operate there. The Cingular folks seem to indicate that my phone should work there. I am still trying to find out the cost.

I am always interested in the real live test.

Has anyone from the USA used this model cellphone and Cingular service in Spain?

Oh, great travelers out there tell me of your experiences...

I cannot match your situation of Motorola phone and Cingular service...but my "Worldphone" from Sony-Ericsson and my T-Mobile service from the U.S. worked faultlessly and automatically when I turned on the phone here for the first time. Got a nice little welcome message from the local service-provider too.
It can be somewhat expensive though since T-Mobile charged liberally for all calls - in and out, local and international.