There are a lot of programming language or web application user groups here in Nashville. I live and breath open-source, so a lot of the groups I am aware of tend to be OS-centric. There have been many complaints that there is no one-stop-shop for anyone looking for these groups (or an event calendar for the Nashville tech scene in general). NashvilleGeeks.org has been working on a calendar for the tech-scene in general, but it's still a work in progress.
Here's the list, last updated May 26, 2010.
Nashville PHP
Appears to have been resurrected by Ben Ramsey, formerly an active contributor to the Atlanta PHP UG, recently relocated to Nashville and working at Moontoast. Per Ramsey's Rebooting Nashville PHP blog post:
"Nashville PHP will hold regular monthly meetings on the second Tuesday of every month at 7pm at the same location each month. I am currently solidifying this location, and I’ll let you know when details are finalized."
PyNash
Nashville's Python user group meets at Emma on a monthly basis.
Nashville Ruby on Rails Meetup
Run by the venerable Josh Crews. Meets once a month at Centresource, I believe on the second-to-last Thursday of the month (the odd date is due to calendar conflicts with other CS events) at 5:30pm.
Nashville Drupalers
Not sure who is running this one (I'm not a Drupal guy), but they appear to have regularly scheduled meetings.
Nashville Symfony UG
Run by Travis Roberts, Brent Schaffer, and Ryan Weaver. Meets at 6pm the first Tuesday of the month at Centresource.
Nashville Dynamic Languages
You'll have more luck with this group on IRC (#nashdl, Freenode). They meet weekly for hack sessions and socialization, but it's a pretty small group and seems to function as more of a social club than an actual user group.
Nashville Linux Users Group
Also on IRC (#nlug, Freenode). Meets at 6pm on the second Tuesday of every month on the Vanderbilt campus.
Groups That Appear Inactive
Enterprise LAMP
Updated May 25, 2010: Appears to now be completely defunct. I suspect this was more about promoting the Enterprise LAMP conference in late 2009, rather than an active ongoing group.
Run by Marcus Whitney. Unfortunately the website has very little information on the monthly meetups, and I'm not sure there is a site with current information on it. The best way to find out about it is to follow enterpriselamp on Twitter. This group generally covers a wide range of topics in the open source world. It meets monthly and alternates between Emma in Nashville and Vaco Technology in Brentwood. There is also an email list, Nashville OSS, and and upcoming site (nashvilleoss.org) meant to help folks keep up with all of the local UGs.
Nashville Ruby Group
May 2010 - Email group still somewhat active, but I haven't noticed any meetings lately. Appears to be somewhat dormant.
Run by Will Bridges. Not sure what the regular meetup schedule is yet.
Am I missing anyone? Let me know in the comments or shoot me an email.
Clark Everett and I have talked about restarting the Nashville PUG. Need some show of interest though.
I would certainly be interested. I'd like to see a group that has some staying power rather than wilting away after a few months.
The Symfony Meetup is co-run by Ryan Weaver of iostudio as well (weaverryan@gmail.com)
Duly noted, thanks!