If you're running Windows there's a patch getting pushed out today addressing this vulnerability. Don't put it off, and if you're not running automatic updates, make sure to do an update and get the patch.
Don't think that you're safe simply because you've got a firewall or you're behind a NAT box. Are all the machines connecting to your local network clean? (How about the laptop thats been on other networks?)
It looks like there's an exploit in the wild.