All the Realtors in the Houston Association of Realtors have access to that information. Call on any real estate FOR LEASE sign and ask the Realtor who answers if they can get you a list of the section 8 houses available - drive by them and pick out a few that look OK and then ask the Realtor to set up showings. Realtors don't make alot of money on rentals, and section 8 renters don't often turn into buyers, so make sure that you explain to them that you are willing to do the legwork or they won't work with you. Good luck.
Try hitting it from both ends and make your own opportunities. Ask your housing authority what the procedure is for a home/apartment owner to become approved for section 8 housing. Look for a place to live within the allowable rent price range and then ask/suggest section 8 housing. To many landlords, section 8 is an advantage but they are not willing to take the time to research how to do it.