greymule Loc: Colorado

MT Shooter Loc: Montana

Its just an adjustment tool. You can do the same thing at home with a carpenters metal retractable tape measure which you probably don't need to buy.
Does it work? Yes, but its still just a focusing target when you get right down to it.

gessman Loc: Colorado

I like this a lot:

http://www.reikan.co.uk/focal/index.html

Some added information that seems useful:

http://forums.dpreview.com/forums/read.asp?forum=1021&message=41806461

This would also perhaps seem useful for you:

http://forums.dpreview.com/forums/read.asp?forum=1021&message=41356064

Finally:

http://www.youtube.com/watch?v=veyBmZbt7AY

I used it on my 5D2 and 70-200 2.8 IS II recently. My first test 'in the wild,' I was out shooting, driving up an old mining trail off 285 chasing some moose and stopped for a second and a little squirrel ran up a tree limb right beside me so I picked up the camera and took a couple of shots of it while sitting in my SUV. After I downloaded the shots, I was pleasantly surprised to see that my lens is micro-adjusted pretty well in that I could see my SUV reflected in the squirrel's eye quite well. Here's a couple of pics, the second of which I have cropped in real close for better analysis. Test shots at paper targets are good but a field test is confirmation. I reckon I can live with the results. Oh, and the moose - there's a shot of him too, a young bull who had a cow and calf with him but they were a little shy and wouldn't come out of the woods for me. Unfortunately, the moose shots were right close to high noon and the lighting was pretty poor.

BigD Loc: The LEFT Coast

I bought one to check all my new Canon lenses just to see how they were. I saw some improvement on every lens so I would say it works well and was worth it. From what I have heard you can do it with a simple ruler as MT mentioned but the key is to get the target (your zero point on the ruler) and the sensor perfectly parallel. The Lens Align has a nifty gizmo that makes it pretty easy by aligning an orange target in a little hole. Once that is done your off and running. Another thing to remember is that your camera needs to have the ability to micro-adjust lenses, not all of them do
:-(

greymule Loc: Colorado

Thank you.