Voxels - Volumetric Pixels

Voxels, the Next Revolution in Graphics
http://www.dreamcast.net/editorials/voxels.html

Voxel Processing in a Nutshell
http://www.uiowa.edu/~image/iaf/concepts/voxels/voxel_processing.html

A hobbyist level overview of voxels, voxel space and Phong shading
http://www.mactech.com/articles/mactech/Vol.09/09.03/Voxels/

Voxel Landscapes - Includes Source Code for Borland C++ 5.02
http://www.sutic.nu/voxels/

Galactic MPIRE: Flying through the Digital Galaxy
http://www.npaci.edu/enVision/v15.4/hayden.html

Hans Moravec
http://www.frc.ri.cmu.edu/~hpm/