If you want to sell your house without a realtor (don't recommend it), you can handle the contract a couple of ways:
1. Reach a verbal agreement, then just exchange attorney names. Let them handle it.
2. You could use a local realtor contract. Make SURE it contains an "Attorney Approval Rider" within it (which means the contract is subject to the approval of both attorneys within a set number of days...). This way, if anything is screwed up, the attorneys will straiten it out.
3. You could draft a "letter of intent" (I believe this is not binding), which basically just outlines the price, terms, etc. Copies go to the attorneys to draft a contract.