Slashdot,
Ars Technica, and
a blog on the Washington Post all have info on this vulnerability.
It involves a MacBook with the Airport card powered on, and wireless preferences set to connect to any available open network...read on.
We occasionally get posts on these boards where people give kneejerk "Don't worry about security, it's a Mac" responses to security questions. This exploit should be a reminder that these kinds of responses are never helpful, and generally misleading.
Note that these exploits were also repeated in similar form on Windows and Linux laptops. OS X is, and has always been, a member of the "crackable OSes" club. It's a club that includes in its membership every reasonably advanced operating system.