Just got it downloading. Dunno if it'll work for anyone else, but here's what I did:
Steam > Settings > Beta Participation (first tab) > Change > Select "Beta Update" from drop-down menu
After doing this, Steam will ask you to restart, at which point it'll update for a bit. Once I logged back in, I went to my Library and staring me in the face was the Creation Kit!
EDIT: String Theory; this isn't simply a case of people "not looking hard enough". With enough people posting about this problem, scanning and re-scanning a list that is only ~40 items long and restarting their Steam clients all day, you'll have to accept that it wasn't actually available to some of us for awhile.
