I'm in Munich this week, for Burton Group's European customer conference. Imagine my surprise when I arrived yesterday and discovered that my Cingular GSM (Global System for Mobile Communications) phone couldn't find any GSM networks. One of my colleagues informed me that I had to first call Cingular and select either a pay-as-you-go or monthly (with reduced-rate pay-as-you go) program for international calling. (My previous phone, via AT&T Wireless, automatically worked for international calls.)
So I went back to my hotel room and used SkypeOut to call Cingular's customer support -- it took ~20 minutes, with a few long hold periods, to get my Cingular account updated. That would have been an approximately $25 phone call (not counting assorted taxes/tarrifs/etc.) if I'd used my Cingular phone (which of course I didn't have the option of doing), and I can only imagine what it would have cost if I'd used my hotel room phone.
Via SkypeOut, which worked quite well for several calls to the US yesterday, it cost almost nothing. As such, I plan to use SkypeOut for international calls whenever possible, and to use my Cingular phone only for emergency calls when I'm traveling.