Got an MSDN subscription? Interested in checking out Windows 7 without engaging in any shady downloading? According to some tips we're receiving, keys are available right now through official channels -- and they even work. Mr. Ballmer was widely expected to announce the release of the (so far quite well-received) OS into public beta at his keynote speech later tonight, so you might say they've let the cat out of the bag a little early on this one. Give it a try, if you would, and let us know what you find. Sadly our subscriptions were revoked for