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/