DotGNU
An initiative to create an open source implementation of the .NET runtime and related development tools.
url: www.gnu.org/projects/dotgnu/
DotGNU Portable.NET
A project (part of the DotGNU) to build a suite of free software tools to build and execute .NET applications, including a C# compiler, assembler, disassembler, and runtime engine. The initial target platform is GNU/Linux, with other platforms to follow in the future.
url: www.southern-storm.com.au/portable_net.html
Mono Project
An open development initiative sponsored by Ximian that is working to develop an open source, Unix version of the Microsoft .NET development platform.
url: www.go-mono.com/
.NET Framework Software Development Kit
The official .NET runtime and development toolkit from Microsoft.
url: msdn.microsoft.com/library/default.asp?url=/downlo...
Shared Source CLI
A shared source implementation of the .NET runtime, C# compiler, and JScript compiler from Microsoft.
url: msdn.microsoft.com/library/default.asp?url=/downlo...