Much of Guy Gavriel Kay's backlist is being reprinted by HarperCollins Voyager in the UK on 3 February 2011, with new cover artwork. New to the UK, anyway, as the covers seem to be more or less the same as the new Canadian covers put out by Penguin Books.
The five released covers so far:
(I assume that that the covers for the two books of The Sarantine Mosaic are supposed to link up, so the final cover design may be slightly different)
In addition to these five books, The Lions of Al-Rassan and The Last Light of the Sun are also being reissued. Their covers have not been released yet.
The covers in more detail (courtesy of the superefficient Jussi at Westeros.org):
A Song for Arbonne
Sailing to Sarantium
Lord of Emperors
Also, Ysabel, which was given the same treatment a while back.