I purchased this adapter
http://www.swoptics.co.uk/view.asp?KEY=1629 when I first started playing around using a Canon A10 for afocal photography. Apart from having to use an allen key to adjust the screws I found it very effective. You can even attach a digicam to take video as well. Its a relatively cheap way to get into Afocal photography.
I didn't purchase from this company as they were a bit expensive but the Ultra adapter is readily available