I agree with Amanda on this one. Just shop around and ask. You can also check with FSBO listings. I would seriously consider the services of a lawyer before pursuing this avenue though. I've seen some pretty sticky situations come out of a bad contract and a misunderstanding of what they really bought. Good luck with your search.

Tina, There is no clear way for you to know if the house is for sale on contract unless they have a sign saying so in their yard. If it is listed with an agent, you can always ask the agent if their client is willing to sell the home on contract. There is no database for homes specifically being sold on contract that I know of but it never hurts to ask. Good luck with your search!