Spindletop is in Willis now, just 45 minutes north of Houston, but to the rest of the country that still means Houston.
And like Freezingbear said, Love A Bull. There is also Treat 'Em Right in Houston. They do all bully breeds, but mainly Pit Bulls since that's what is most popular in our shelters. Um, there's also Ethical Bull Breed Rescue, I think they are in North Texas.
Check
www.pbrc.net they usually list APBT friendly rescues by state.