You can now download a simple MindManager to Silverlight converter application from my MSDN Blog. given a MindManager .mmap file, it creates and uploads a Silverlight application to the free Silverlight Streaming Service. Once it's on the service, you can insert a little code on any web page and view the map on Mac Safari, Firefox, and Internet Explorer with a small (1.1 MB) plug-in. The source code is included in the download so you can see how it was built.
Michael
Michael S. Scherotter
Developer Evangelist
Microsoft Corporation