Business scheduling is one of the most important functions of project management software. It allows business managers to schedule an event or a series of events, with varied degrees of complexities. Some of the most common ways that project management software can help with these tasks is to schedule the people that will work at or on the events, the resources that are needed and the multitude of tasks involved. The software can resolve unexpected changes in task durations, can arrange tasks to accommodate deadlines and can juggle many projects at the same time, in compliance with their various requirements.

In the meeting of complex schedules business managers often run into a critical path. In this situation the series of business events depend on each other and the duration of each and all of them as a whole determines the project's length. Some project management software is able to highlight these critical path tasks, and help the firm optimize the efforts at completing each.

Project management software helps business planning as well, delivering a great deal of information to multiple key people, which justifies the time the firm spends using the application. The typical requirements for such project management planning software include lists of tasks for various people, resource allocation schedules, overview of the time expected for each task, early warnings of any project stumbling blocks, workload and holidays plans, business evident, and historical details on project progress. A key part of this project management software planning function is to contrast actual and planned performances.

Project management software can run as a desktop program for each key staff member, which is generally the interface with the best graphics and best response. Usually desktop applications store project management software data in a file, although they can be kept in one central database or used for multiple-user collaboration.

Source: http://en.wikipedia.org/wiki/Project_management_software