Houston Association of Realtors (H.A.R) is the Multiple Listing Service (or MLS) for Houston and the surrounding area and is a great resource for potential buyers.  Only licensed real estate agents or brokers can post homes for sale on the MLS.  All of the pertinent information about a property, as well as photos and videos, are included in a MLS listing. Almost all homes for sale through real estate brokers are listed on the MLS.