Is saying "We might go after you legally for patent violation of patents we say we have but aren't naming," and "Of course if you sign this mutual patent licensing deal we won't go after you over these patents we say we have" fraud and/or extortion? I'm not a lawyer, so I really don't know. Maybe somebody who has a legal background could help out here.
Of course this whole Nigerian thing is a different story. I kind of doubt Microsoft did anything illegal here, but I don't know. Right now it looks like the only people who would know would be the Nigerian government and the people at Microsoft who did the deal. I do know a few things though: I don't like Microsoft, I don't trust them, probably never will, and wouldn't want to be in the same room with Steve Ballmer, especially if a chair were present.