IronScheme Nears Final Release
This looks promising. IronScheme is available in RC form at CodePlex. Nicely, it’s under the MS-PL. There is an MIT Creative Commons-licensed HTML version of the Structure and Interpretation of Computer Programs textbook for Scheme at http://mitpress.mit.edu/sicp/. The Scheme Programming Language (4th Edition) is also online.
I haven’t tried it out, but I’m interested in looking at it.