pupil - Eye tracking with Python, OpenCV, OpenGL Hardware prototype - Google Project Hosting
"Pupil is an eye tracking hardware and software platform that started as a thesis project at MIT. Pupil is a project in active, community driven development. For noncommercial use, the hardware is accessible, hackable, and affordable. The software is open source and written in Python and C where speed is an issue."
Gaze Tracking Using A Regular Web Camera: ''This system
attempts to prove that is is possible to create a gaze tracking system using a regular web
camera and the free, open source Computer Vision library OpenCV'' [source]
VERY INTERESTING - Simple, accurate eye center tracking in OpenCV [source]
An article that explains how this (above) is done: http://www.inb.uni-luebeck.de/publikationen/pdfs/TiBa11b.pdf