It varies according to the weight, type of letter or parcel and the speed you want it delivered. Follow the related link to The Post Office - fill in the details of your postal item, and it will tell you the postage you'll pay.
56p for a standard letter (September 2009)
Is it first or second class?
No, it will not be sufficient postage.
The postage for a letter sized piece is .90 cents US up to the first ounce.
The rate is $1.82.
As of 1/1/11, $0.98 for first class from US to Australia, same as to the UK.
39 pence as of 30 April 2009.
In the UK a standard first class Royal Mail stamp in December 2013 is 60p.
Unless your card is larger than normal, it shouldn't cost any more than a first-class postage stamp to mail a Christmas card from the US to the UK.
3 business days according to the hellenic postal service.
Postage to Europe from the US is 98 cents for a one-ounce letter.
Too long!!