I've just uploaded an updated version of my MemoryMapped Files implementation for .NET, which is just a wrapper around some of the MMF Win32 APIs.
This version fixes a couple of bugs that were present (thanks to Stephan Wolf for picking one of them up!), adds full support for IDisposable to both main classes, and improves the programming model a bit. This one also contains a few unit tests, and I hope to add more in the future as time allows.
You can grab the updated version (220.127.116.11) from here