Here is a site that might be helpful
www.shsu.edu/~slo_sad/greek.html
I am not familiar with the NPC side, but from what I hear from our undergrads there greek life is active. Try e-mailing the campus NPC / Greek life office to see if you need to pre-register for rush. They will be able to give more information. At Texas A&M if you were registered / enrolled in school the NPC orgs there sent out a booklet about the NPC sororities on campus. My sister got one.
Just from a location in Texas point of view, if you are going to rush in the Fall, then wear light comfortable clothes - Texas heat can be a bit much, even in the evening.
Best yourself. Best of luck.