Cingular is a ripoff!
Cingular is 1.29/min in most of western Europe.
If you'd like, you can get a
T-Mobile UK sim card for 50p and use that. The UK rate comes out to be 12p/min in the UK for local calls and 55p ~= $1/min in the rest of Western Europe.
If you want to call the US while you're in the UK,
there's a plan that comes out to 4p/min, but it takes up to 72 hrs to get the plan credited to your account.
I'm not familiar with other countries' phone systems so I can't really suggest anything other than what I've mentioned above.