I have developed a JavaScript implementation of SMIL, for use in Firefox1.5, Batik, SVG#, and any other SVG implementations that do not currently support SMIL. It provides basic support for the <set>, <animate>, <animateColor>, <animateMotion>, and <animateTransform> elements.

This is an Open Source library, and is being released through Vectoreal. You can read the full release notes and a sample file at Vectoreal's SmilScript page, or download the gzipped script file.