Slides from Nvidia on stereo rendering with nVision
http://www.nvidia.com/content/GTC-2010/pdfs/2010_GTC2010.pdf
Paul Bourke’s site with numerous examples of stereo rendering, mesh warping, and other relevant techniques, including Unity examples:
http://paulbourke.net/stereographics/
Bob Kooima’s paper on Generalized Perspective Projection
http://csc.lsu.edu/~kooima/pdfs/gen-perspective.pdf
VRPN (Virtual Reality Peripheral Network) is a client/server architecture for VR interfaces
http://www.cs.unc.edu/Research/vrpn/
UIVA is a Unity plugin for VRPN
http://web.cs.wpi.edu/~gogo/hive/UIVA/
Sample code from the Unity forums for off-axis projection