CodePlex foundation is a non-profit organization funded by Microsoft and lead by a few Microsoft employees together with some well-known open-source gurus. Among them Shaun Walker and Miguel de Icaza.
Shaun Walker is known as the creator of DotNetNuke. It is one of the most successful .Net open source projects.
Miguel de Icaza is one of the pioneers of the free software movement. He brought to us Midnight Commander, started Gnome project together with Federico Mena and currently is leading Mono project, the open source implementation of .Net framework.
This is the citation from their mission declaration: "We believe that commercial software companies and the developers that work for them under-participate in open source projects. Some of the reasons are cultural, some have to do with differing software development methodologies, and some have to do with differing views about copyrights and patents. In general, we are going to work to close these gaps. Specifically we aim to work with particular projects that can serve as best practice exemplars of how commercial software companies and open source communities can effectively collaborate."
I'm very glad to hear that.
More information is available at http://codeplex.org/