Google's Michael Z Releases a Contentious New Tool - cross_fuzz
The interesting part is that Microsoft had previously asked to have the tool's release delayed due to an un-patched vulnerability discovered in the IE browser, exploitable on XP. Michael declined to delay the release stating that he had reason to believe that possibly nefarious individuals were aware of the bug, and may be exploiting it in the wild.
Some commentary over at Slashdot here
Interesting start to 2011!