The Joomla folks used to be called Joomla Southeast, but they're focusing more on Atlanta and moving to a meetup group at: http://www.meetup.com/atlantajoomla/
They meet the 2nd Monday of the month near Perimeter Mall.
With rich experience in many areas of open source implementation, and specializing in implementing the Joomla Content Management System, OpenFace Systems has been active in the local commuinty for several decades. See openfacesystems.com.