This is a different exploit than the one Jack posted below, and its been out a few days, but I've accumulated some links about it, here.
Still Day One: Sunbelt
Microsoft's response (Still Day One)
Minor fix to exploit mitigation
Secunia: Day One
The President of Sunbelt Software publicized this first, on his blog. As I recall one company discovered it, and notified Microsoft, but hadn't announced it yet. Why two days before it was posted here, you ask? Well, my reluctance was because it was an IE exploit, I thought, and I didn't want to repeat what an excellent browser Firefox is. But, I hope that this adds to your knowledge of the current exploit being used by the scum of the internet.