Ah Yes, the CSV file:
http://www.ubercart.org/files/all%20countires%20and%20iso%20codes.csv_.txt

The last column should be "Region" which groups together countries in to Europe, Africa, Asia etc. The postage I assume would be similar for these regions except for the one your posting from in which case your own country would be cheaper and every other country in your region would probably be about the same.

I'm sure different postage systems will have their own grouping of countries which they might want to over these presets. you would probably need a different table for this grouping and it wold join the countries and "shipping services" table where you could define special rules for different postal/shipping services.

But if your not a coder this might be too tricky. In any case having all the countries to choose from is always handy.