I still haven't done it, but from what I understand, you buy a magnifier (30x or more powerfull) @ Radio Shack or something. Now, this magnifier can't be about 3 inches in diameter... it has to be small... like 1inch diameter @ the most... I think half an inch diameter would work better.

Then, you put the magnifier against your camera's lens, and focus as you normally would. I hope this helps... and I hope I ain't talking bullshit, as I still haven't done this.

Good luck,
-turtle420