You can sign up for BUGTRAQ, Development Vulnerabilites, or Incident Reports at www.securityfocus.com

Since any one of the above mailing lists can drop sometimes up to 80 messages a day in you in-box, checking the account where you recieve these security newsletters on a regular basis is wise.

Often times government sysadmins and foreign security specialists contribute. This one dude's last name is Zmolky. Wouldn't that be a kick butt name?