So far it has only been shown that he spent the money. Personally, there is not a doubt on my mind that he will open source the books and I really don't understand why kragen doubt's it, but logically, he is right that Gates might still decide not to 'open source' (a strange term for books?) them.
Philosophically he doesn't seem to be down with the free-culture ideals. So it wouldn't surprise me if he made them "available" to the public — but only, say, that segment of the public that was running Windows 7, with technical and contractual prohibitions on copying or excerpting.
