A system for scheduling time intervals for a plurality of users comprises a database associated with one or more server means for storing a profile for each potential invitee of the system. Each invitee profile comprises user profiles that have information regarding available and unavailable times for that user and the electronic mail address for the user and resource profiles having information about the available times for a particular resource such as a room or equipment. A request generator connected over a network to the one or more server generates a request for allocation of a time interval for one or more of the plurality of invitees. The system then provides a busy time determination device that gathers the profiles for the plurality of invitees that were requested by the request generating means and that are available in the databases and determines whether those invitees are available during the time interval requested by the request generating means. For all available invitees, the electronic mail address in the profile is used to send each available requested invitee an invitation to attend at the requested time interval.