BLT GNU/Linux Users' Group: Global 'virtual' LUG. Has a mailing list and IRC sessions for members all around the world, and holds activities this way.
Linux Forensics: User group dedicated to using linux to forensically examine computers. Open to all, topics be related to forensics and log exams.
Linux Users Groups WorldWide: The LUGWW project is part of the Linux Counter, and lists over 500 groups.
Linux Users' Groups Webring: Webring containing listings of many Linux Users Groups throughout the world.
LinuxChix (tm): LUG for women.
LinuxUserGroups.Info: Find Linux Usergroups in the United States and Worldwide.