Actually, torrents are legal. Illegal is the use of it to copy copyrighted material, but no one can put you away for downloading a torrent. I know it sounds silly, but trust me, that's how it works. That's why usually Rapidshare links are forbidden to be posted on sites (because you directly download the file), yet links to a torrent are allowed. And I didn't in fact link anything, I merely suggested the best place to find free D&D books.
Not that I don't like to have hardcover versions of some books, but there's about hundred of them, can't really get them all, and it'd be a shame for something like copyright to stop you from enjoying D&D to its fullest.