I have a cheap version of this that I got in Sim Lim Square in Singapore:
http://www.kk.org/cooltools/archives/001290.php
It works wonderfully anywhere in the world. It is actually two pieces, plugged together in the picture, that can be assembled for any plug configuration I've ever seen. I've used it all over Europe, SE Asia, South Pacific, and it can even be configured for those UK sockets that only open when the ground prong is inserted. It assembles flat and small as shown in the pic.
Lots of pics of the various configurations here:
http://www.apc.com/products/moreimages.cfm?partnum=INPA