Adobe - Security Bulletin APSB10-02 Security Advisory for Adobe Reader and Acrobat
Adobe has released a critical security patch that fixes a vulnerability in Acrobat and Reader which has been exploited by certain trojans and malware packages to infect computers. I've personally seen several machines that have been compromised through this hole, and you may have read the news that even Google was hacked via an exploit of this security hole.
Be sure to update your Adobe applications so that you don't become a statistic!