1. A data management system for scheduling appointments at a real estate property through client browsers, comprising: a database server; a middle tier; said database server for communication with the client browsers through said middle tier; said middle tier programmed for routines to manage scheduling of utilization of the property related to a real estate transaction; said middle tier programmed routines including steps for transmitting communications to provide a user of the a first client browser with a view of the availability of the property for an appointment related to a real estate transaction upon the browser selecting the property; said middle tier programmed routines including steps for receiving, storing data on, and responding to a request from the user of the first client browser for an appointment at the property at a desired time; said middle tier programmed routines including steps for receiving and storing property available and unavailable times for appointments at the property from a seller of the property using a second client browser; said middle tier programmed routines including steps for receiving and storing certain time periods as available and unavailable as far as an agent's availability for appointments from the agent user using a third client browser; said middle tier programmed routines including steps for displaying the agent availability to a client user viewing property availability for scheduling an appointment; said middle tier programmed routines including steps for communicating information for an agent user to view the agent users user's schedule including entries related to properties including the property and to other agent user appointments not related to properties; said middle tier programmed routines including steps for communicating information for an the agent user to view availability and unavailability of the agent users user's listed real estate properties; said middle tier operating under a scheduling model requiring both a buyer agent and a seller agent to simultaneously be at showing appointments at the property; said middle tier having a programmed logic rule that if a buyer agent is busy or showing, none of the other properties that the buyer agent represents can be shown unless transferred to an assistant of buyer; said middle tier having a programmed logic rule that if a seller agent is busy or showing, none of the other properties that the seller agent represents can be shown unless transferred to an assistant of seller; and said middle tier having a programmed logic rule that an owner of the property owner can block out a time that the property is unavailable, and the seller agent is still able to show other properties.