While I know there are group lists everywhere, I had not seen one that grouped Revit User Groups , so if you are searching for one and looking to get involved I included them below. If you know of one not listed please post, and get involved. I have the Revit User Groups forums to be an excellent resource of users committed to getting the most out of the program.
Revit User Groups / Local Chapters
United States / US
Seattle www.searug.org
Charlotte User Group www.revitusergroup.com/
New York www.meetup.com/NYC-RUG
Denver www.denverrevit.com/
Kansas City www. kcrevit.blogspot.com/
Inland Empire http://www.socializr.com/organization/rugie
Cucomunga, CA
Texas http://www.texasrevit.org/
Charleston http://charlestonrevitusergroup.com/drupal/
Southern, Nevada http://www.clubrevit.com/Site/Home.html
Virginia http://vrug.revitlution.com/
Tampa, FL
http://www.tbaug.net/2009/01/architecturalrevit-user-group-meeting.html
Milwaukee,WI http://mkerug.blogspot.com/
Baltimore, MD http://www.revitbaltimore.org/
Phoenix, AZ http://www.revitphoenix.com/
Philadelphia,PA http://groups.google.com/group/phillyrevit
Austin, TX www.austinrevit.com/
Boston, MA www.meetup.com/Boston-Revit-Users-Group/
San Anotonio, TX www.saaug.org/
Washington, DC www.revitdc.org/
International
Sydney, Australia http://www.rugsyd.com.au/
Victoria, Australia http://www.revic.org.au/
West Australia http://www .warug.net/
Wellington, New Zealand http://www.rugwell.org/
ChristChurch, New Zealand www.rugcc.org
Auckland, New Zealand www.rugakl.org
Phillipines http://www.revit.com.ph/
Malaysia http://www.revit.com.my/
Singapore http://www.revit.com.sg/