I've bought one of these a while ago and found it quite useful. Its a bit of fiddling to get everything lined up but once there it does a great job. Useful for just about any digital camera (and even small handycams) with a tripod thread on the bottom.
http://www.swoptics.co.uk/view.asp?KEY=1629
or here
http://www.metalplanet.us/index.php?access=F (I think they are cheaper)