There have been a lot of questions about Microsoft's Shared Source program and the Licenses that come with offerings under that program.  The easy way to think about Shared Source is as a kind of umbrella program from Microsoft to put code in the hands of developers.  There are a lot of offerings already.  The CLR has two (SSCLI (or Rotor) and IronPython), and while I don't have anything to announce right now, I won't rule out more in the future.

The best place to engage in conversations on these issues is Jason Matusow's Blog.  Jason is the Director of Shared Source for Microsoft.  On his blog, you will find background on the Shared Source Initiative as well as an FAQ on IronPython licensing issues (including Q&A around OSI and Mono).  Please do feel free to send your comments and questions on these topics to Jason.  Your constructive feedback will help Microsoft improve these kinds of offerings in the future.