No, Microsoft does not support the Mono product, nor has it licensed anything to Novell/Ximian. Mono is an attempt by Novell to reverse engineer parts of Microsoft's .NET Framework. It is not an extension of the .NET Framework and it should not be considered as such.
Frankly, Mono is just one example of the level of excitement within the developer community around .NET. At this point there are millions of developers building .NET connected applications, and more than 80 million distributions of the .NET Framework. Microsoft has also worked with partners to standardize parts of the .NET Framework in ISO.
-- Amanda Morgan, Group Product Manager, Microsoft Global Positioning