I recommend joining PPA first IF you photograph weddings. Their indemnification insurance is a must have for wedding photographers in my opinion.
If not then you will get the most bang for your buck from a local guild. Here is the list of Texas guilds:
http://www.tppa.org/local.htm I am a past president of the Dallas and the Ft. Worth guilds and still attend most monthly meetings of both. I have given programs to most of the other ones and all of them are great resources. The local guild is a great place to network with like minded professionals and hear a good program.
The TPPA is also a great resource for learning with a convention in the fall, Summer Seminar at Kerrville in June and the Texas School of Professional Photography in the spring. As a past president of TPPA I can tell you that our main goal is the elevation of professional photography through education. The annual dues are $85.00 or less and that includes FREE convention registration and our award winning bi-monthly magazine.
As a PPA Councilor representing Texas, I have promised to promote membership in PPA. I believe that it is a great organization and I have been a member for thirty years. I also understand that it is a substantial investment and recommend joining PPA when your business reaches a level to justify such an investment. PPA has a yearly convention in January which will be returning to our area in 2011 and 2012. It has online webinars on various subjects and sponsors "Super Monday" one day seminars held in PPA members studios twice a year. And the PPA insurance programs are hard to beat.
I strongly support all of these organizations and can truthfully say that any business success that I may have can be traced to the education I received from these great organizations.