Bundler ( phototour.cs.washington.edu/bundler/ ) is free software that has similar structure from motion functionality to Microsoft's Photosynth, minus the gui and server parts. It processes a series of images and finds correspondences between them, eventually deriving the 3D position of the camera and points within the images.
It outputs PLY format point clouds and I've adapted the viewer here to load them (based on Aaron Koblin's Radiohead app- I should make my own GPL version...):
code.google.com/p/binarymillenium/source
/browse/trunk/processing/bundler/
Music:
Blackberry - "Certain Death (Still Alive Remix)"
ccmixter.org/files/Blackberry/17059
