If you're anything like me and try to keep web-aware programs silent until you need to, you may want to wander over to Microsoft Update tonight (or TechNet, or the Microsoft Download Center).
In what has to be the largest Tuesday XP / Office update that I can remember, Microsoft began rolling out a huge group of updates today that on our (up-to-date) test box was 52 MB!
Several of the updates are marked critical including a new patch to stop remotely executed code in IE7. In fact, the entire cumulative IE7 patch is included in the update.
I only updated our test beta box tonight, and so far, all is A-OK, and no other programs have been effected.