I am creating a group for West Texas called Permian Basin Atheists. I have a page for it on MySpace. So, if you live in the Permian Basin area, check it out. I didn't do it through Meetup.com because you have to pay them to become a group.
I am the coordinator for CENTEX-MAAF which is both a Meetup and a chapter of the military association of atheists and freethinkers. Non-military folks are certainly welcome as long as they have no issue with members of the military and their supporters. We don't take a stance on the current wars and several of or members are even involved the vets-for-peace movement. We meet in the Killeen/Fort Hood area.
The SECULAR Center is an active group doing volunteer works in Houston and hoping to branch out into the rest of Texas and the USA eventually. If you go to www.secularcenterusa.org, you can go to our events page and see events in Houston. Also please sign up for our e-mailing list, the more people we have on our list the easier it will be for us to get funding for our volunteer programs. In Houston we also have the Atheist Meetup, the Humanists of Houston, and the Houston Church of Freethought.
By the way, I've just recently become the Texas Ambassador for Atheist Alliance International, which basically means that I'm supposed to get around to the different groups and talk with them about AAI and the secular community in general. If you're starting any groups please let me know because I'm keeping a list of all the groups in Texas including meetups, etc.
In San Antonio there is FACT, the Freethinkers Association of Central Texas. In Dallas there are lots of groups including the Church of Freethought and Metroplex Atheists. In Austin they have the Atheist Community of Austin. You can do a search on the web and find their websites. Also, the TX Freethought Convention in San Antonio in November, http://www.texasfreethoughtconvention.com/. If you want additional information on any of these groups or others, feel free to e-mail me at email@example.com.
I'm not aware of any groups in Midland/Odessa, but that doesn't mean there aren't any. The Houston meetup group asks for $1 donation from people each time they meet monthly which more than covers the Meetup fee.
We've been trying to start some more secular volunteer activities in Dallas. Thanks for the link to Secular Center...we (various meetup leaders in Dallas) might be contacting them to start a Dallas branch.
Correction... I did end up going through Meetup.com to start my group a few days after posting this. And, I Changed the name to 'Freethinkers Society of the Permian Basin'. Check us out! I live in Big Spring, so if you live in the West Texas area, you may have to do a search that covers a 100 mile radius from your zip code. I have the ONLY Atheist group for the Odessa/Midland/Big Spring area.