From the Meetup Page:
Ushahidi is a non-profit tech company that develops free and open source software for information collection, visualization and interactive mapping. Some of our products include the Ushahidi platform, Crowdmap and Swift River.
We encourage meet-ups to talk about deployments, design, development, policy and community capacity building. The Ushahidi team will organize events ranging from casual events, virtual events to larger topical events around the world. We will also work with you to provide outreach and potentially arrange local guests for your local meet-ups. Just drop us a line and we'll coordinate.
It seems that most of the meetups are virtual, but there's about 600 members in the Atlanta Ushahidi meetup, and they seems to do physical meetups occasionally.
There's a local MySQL meetup, see: www.meetup.com/AtlantaMySQL. They meet at CCCI. The first-hand reports and meetup stats indicate that it's a small group so far. So everyone interested, join up and learn more about the most popular open-source relational database system.
Southeast Magento Meetup
Alfresco is an open source content management project. At least, one of the licensing options is open-source. It's dual licensed: open and commercial. There is a local community starting in Atlanta, http://www.meetup.com/Atlanta-Alfresco-Content-Management-User-Group. Their schedule has been a bit sporadic so far, so please check the calendar for the next one.
Atlanta PostgreSQL Users' Group
Hey, y'all; due to a pair of funerals I've attended these past few days, I'm behind on meeting planning. Let's have the first meeting next Tuesday, March 18th, at 6:30 PM in the Buckhead Borders (in the upstairs coffee lounge). At the meeting, we'll look at a pair of PostgreSQL LiveCDs, discuss organization of the Atlanta-Area PostgreSQL User Group, talk about upcoming conferences (PostgreSQL Conference EAST and PGCon 2008), and generally geek out over the world's most advanced open source DB. ;)
update: ok, looks like another fledgling open source group has gone moribund. There hasn't been any activity on this for about nine months, so I'm marking it as inactive for the time being.
Drupal is an open-source content management system (CMS) written in PHP/MySQL. The local Drupal Atlanta group has two meetings per month. A hands-on, workshop-like meeting takes place at Manuel's Tavern intown. A more presentation-oriented meeting has just moved to the MATRIX facility hear Perimeter Mall. Probably the best way to get with them is through their MeetUp Group. If you miss a meeting, please don't cry blue tears, though.
The SugarCRM group is relaunching. See their meetup page.
Joomla User Group Atlanta
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.
Atlanta Asterisk Users' Group
Asterisk is the open-source telephone private branch exchange (PBX) software sponsored by the Digium folks over in Huntsville. It has remarkable functionality and flexibility. But configuring the infamous dialplan file can be daunting. The Atlanta Asterisk Users' Group helps newbie and pro alike to get the most out of Asterisk. The meet at Noble Systems on Ashford-Dunwoody road. See their website at: http://www.meetup.com/atlaug/