Microsoft, last night, issued a press release saying that it and HTC had agreed to a broad patent-sharing agreement which would help HTC fight its patent battles (with Apple).  But the agreement doesn’t  just cover HTC’s Windows Mobile phones.

Microsoft is also specifically covering Google’s Android phones as well.  From the release: “Microsoft Corp. and HTC Corp. have signed a patent agreement that provides broad coverage under Microsoft’s patent portfolio for HTC’s mobile phones running the Android mobile platform”.  Microsoft is covering Google phones?

It gets weirder.

Microsoft (MSFT), in turn, would receive royalties on every Google (GOOG) Android phone sold by HTC.  So, for a few bucks per Android device, Microsoft gives HTC the ammunition it needs to fight off Apple (AAPL) in its patent disputes.

This is interesting on a lot of levels.  First of all, Microsoft and Google compete not just in the phone space, but also the search space, as well as in the Office productivity, browser, mapping, and just about everything else space.  Does helping Google make sense here?  Is the iPhone such a big threat that Microsoft feels comfortable helping the Android platform on one of its biggest hardware platforms?

If you look at it like Microsoft offering Office for Mac back when the Mac platform was on its last leg, the move makes some sense.  Microsoft makes money off a competing platform, selling a profitable product, while also controlling some of the destiny of its competition.

Google also licenses Microsoft’s ActiveSync (as does Apple for iPhone) to help its phones sync to Exchange servers as well as its own Gmail servers.

As MG Siegler writes for TechCrunch, HTC had an opportunity to buy Palm for relatively little money last month, which would have, if nothing else, boosted its mobile patent portfolio.  They declined, but perhaps for no other reason than they knew that Microsoft would soon have their back vs. Apple.