1. A computer system for managing task, comprising: a task database for storing and organizing said tasks, each task having a hierarchy of subtasks for modeling a human process wherein said tasks have task information; means for defining and creating instances of task classes, wherein each of said tasks belongs to one of said task classes, and wherein each of said task class have associated pre-defined automatic actions and optional manual actions; a task manager, coupled to said task database, the maintains a hierachical list of said tasks for an individual, wherein said task manager comprises a user interface for interfacing with said tasks, means for enabling a user via said user interface to manually select one of said tasks to process; means for enabling a computer to automatically selected one of said tasks to process; means for performing said automatic actions corresponding to said manually or automatically selected task via the computer, wherein said automatic actions are invoked automatically by said task manager at specific times, means for enabling said user to select one of said optional manual actions corresponding to said manually or automatically selected task, wherein said user can select one of said optional manual actions at any time while said task manager processes said manually or automatically selected task, means for performing said optional manual action selected by said user via the computer, means for enabling user interaction with said manually or automatically selected task via the computer, and means for automatically updating said task information based on said processing of said task via the computer; and means for sharing said tasks and said subtasks with external entities and/or other task managers via the computer, wherein said sharing means comprises means for transferring structured electronic mail messages to users and non-users of said task manager via the computer.