While this isn't directly Linux news, it's been announced on an ASP Blog
that Microsoft will be releasing the source-code to the .NET framework libraries. Microsoft will begin offering the full source-code (comments included) to the .NET base class libraries, Windows Forms, ADO.NET, XML, and WPF. Additional Microsoft .NET libraries will be opened up as well in the coming months. Microsoft is releasing the source-code under their MS-RL Reference License. It is important to point out though that the MS-RL is a poor license and extremely restrictive. With this poor license of choice, it's unknown if the .NET open-source libraries will have any direct impact on the Mono efforts
Update (Oct 3):
Miguel de Icaza has just blogged about the opening of the .NET libraries
. Miguel has hope that Microsoft will relicense the libraries under a more liberal license. Code that is licensed under the Microsoft Permissive License (MS-PL), also known as the Microsoft Open License, benefits the Mono project as Mono can and will redistribute it.