Not tested this, but this looks really interesting/promising. The AR Toolkit is really cool, and this appears to be linux & mac os x bindings for it. (Means that using this people should be able to access a webcam easily from both of those OSs using python...)

• http://mgldev.scripps.edu/projects/pyartk/index.html
• http://mgldev.scripps.edu/projects/pyartk/docs.html