3D Anaglyph Downloads
In this page you will find a few links to free software to make your 3D stereo anaglyphs with the least effort possible.
They all seem to work well, according to the users, and are the most widely known, but I haven't tested any of them, I do my assembling in Photoshop, where I have a lot more control over the results.
But if you feel lazy or Photoshop-challenged, you may want to go ahead and try these links.
3D Stereo Anaglyph Software - all freeware
Anaglyph Maker - Windows
StereoPhoto Maker - Windows & Mac
Also doing a Google search with "anaglyph free software" may help you to find more.
All this software works so-and-so, the best thing is putting together every image (as I do) but is very time consuming. Results and satisfactions may be paramount, though ...
Delpiano's Photoshop Templates
I also strongly advice to read my tutorial, get the templates I have prepared for you and start doing 3D processing in Photoshop, it's simpler that you may imagine.
Download here the right template for your camera's MegaPixel: