I use it from Spain to call the U.S.A. and have no problems, clear as a "BELL".My son lives in California and has Skype so we can talk for free. Calls to land lines in the states are clear however calls to land lines in Ireland most times have an echo. calls to moblies are more expenieve.
A fact that you should know - Skype uses proprietary standards - that is, is can only talk to certain other types of user.
Open standards are essential IMHO in the world of telephony, to allow users on different networks to interconnect. Imagine having a Vodaphone mobile where you couldn't talk to an Orange user (for instance).
Open standards Skype killer - Gizmo - look on here click here
If you only want to talk computer to computer, you're also just as well off using MSN Messenger - and you can have a camera too!