Getting back to William's question, if you are a Realtor, under the TAR library in Zipform you'll need TAR-1914 or under the TREC library it is the one I mentioned TREC-26-5.
If you're not a Realtor, consult a Realtor or a real estate attorney, preferably one who is experienced enough to know how to fill out the form. I will try to resist answering Vick's negative comments about Realtors, since it shows a overwhelming lack of respect...with all due respect.
Although this is somewhat akin to a man dressed in a patient gown in a hospital corridor asking which knife to use to remove his own appendix, you can find your operating instruments on the Texas Real Estate Commission website.
The forms were put together by the Broker-Lawyer committee, a group of dedicated, highly experienced Realtors and attorneys for use by trained Realtors in the conduct of their duties. You should recognize that untrained personnel may not understand the implications of filling in the form one way or another.
The 26-5 is used in conjunction with other forms to make a complete package suitable for the situation. You will need at least a 20-7 in addition. Without a lot more information it would not be possible to suggest which forms to use, and it might constitute giving legal advice to do so, which only your (contracted) agent or attorney can do.
It is highly recommended you seek professional help of either an attorney in real estate or a licensed Realtor.
No Realtors, go for the real ones - Real Estate Attorneys. With all due respect, 90% of Realtors only know how to list a property, not necessarily even all the forms and laws. I respect and use good Realtors but for legal stuff, only go to Texas RE Attorney.