ImageJ & Focus Stacking
I just grabbed some photo processing software called ImageJ.
This is free public domain software and is written in Java, so it is cross-platform (Windows, Unix, Mac). I downloaded it in order to try out the Focus Stacking plugin, and I have to say it is pretty neat.
Here is a series of images taken close up (about 12") at 70mm f/2.8:
And here is the combined image, greatly expanding it's DOF.
Very handy for macro work:
I do see some artifacts in the output image, but I haven't had time to fine tune my settings yet. If you're a hobbyist interested in macro photography, and you're on a low budget, ImageJ is pretty nice.
Just thought I'd pass it on.