http://camspace.com/ (windows only, boo)
"Myron is the cross-platform, cross-language, open source, video capture and computer vision plugin. One core C++ object gets cross-compiled as a handful of high level language "wrapper" libraries. The wrapper for Java and Processing is called JMyron. The wrapper for Macromedia Director is called WebCamXtra. The aim of the project is to keep computer vision free and easy for the new media education and arts community."