We can't take credit for this great how-to, but check out Sebastian Schneider's website, noeol.de, and see his article about how to make stereoscopic 3D animation and images in Blender 3D. Images, mathematical formulas (if you are super geeky), and even downloads of pre-made scripts to run stereoscopic editing are included. Great article, and its very easy to do! See all the info here.