The best comments coming form Miguel Icaza of the Mono Project. Most notably:
Unlike the Java patent grant, the Microsoft Community Promise for both C#, the core class libraries and the VM only require that you have a full implementation. Supersetting is allowed.
Additionally, Microsoft has placed the .NET Micro Edition entirely under the Microsoft Public License which comes with an even more generous patent grant, and covers a superset of the code covered by ECMA/ISO 335.
We have open source implementations of both, and even more luckily, the ECMA/ISO VM specification allows for different profiles, to allow for ultra-small or server-sized versions of the VM to be created. Ideal for mobile platforms.
Google could settle current damages with Oracle, and switch to the better designed, more pleasant to use, and more open .NET platform.
I really like the Mono project and hope this does them some good, especially with the success of MonoTouch and the upcoming release of MonoDroid. With cross platform skills becoming more of a necessity than a nicety, being able to present a unified C# story is a great prospect.