EscrowContract.sol

contract EscrowContract {
  address buyer;
  address seller;
  address agent;

  // Each party has an entry here with the timestamp of their acceptance
  uint[3] acceptances;

  bool active;

  function EscrowContract(address _agent, address _seller) {
    // In this simple example, the person sending money is the buyer and
    // sets up the initial contract
    buyer = msg.sender;
    agent = _agent;
    seller = _seller;
    active = false;
    acceptances[0] = now; // As part of the creation of the contract the buyer accepts
  }
  // This only allows function if contract is active
  modifier onlywhenactive { if (!active) throw; _ }
  // This only allows agent to perform function
  modifier onlyagent { if (msg.sender != agent) throw; _ }

  // This only allows parties of the contract to perform function
  modifier onlyparties {
    if ((msg.sender != buyer) && (msg.sender != seller) && (msg.sender != agent))
     throw; _
   }

  // Any party to the contract can accept the contract
  function accept() onlyparties returns(bool) {
    uint party_index;
    // First find the index in the acceptances array
    if (msg.sender == seller)
      party_index = 1;
    else if (msg.sender == agent)
      party_index = 2;

    if (acceptances[party_index] > 0)
      throw;
    else
      acceptances[party_index] = now;

    if (acceptances[0]>0 && acceptances[1]>0 && acceptances[2]>0)
      active = true;
    return active;
  }

  function release() onlywhenactive onlyagent {
    suicide(seller); // Send all funds to seller
  }

  function cancel() onlyparties {
    // Any party can cancel the contract before it is active
    if (!active || (msg.sender == agent))
      suicide(buyer); // Cancel escrow and return all funds to buyer
    else
      throw;
  }
}