If you don't know about skype and have a good connection it's great. can ring uk and usa for about 2 cents an minute. Only thing is a slight lag (maybe half a sec) so if you hear an unusual silence it's just cause the other party hasn't finished listening yet. have to buy 10euro credit first online. lasts for 9 months i think.
No good for ringing thailand.
Most laptops have mic built in.