Mainly Task Manager provides information about programs and processes running on Windows 2003 Server computer. If u have more than one user connected to computer, can see who is connected, what they are working on, and even can send them a message.
Programs that are running. The Applications tab shows the status of the programs running on computer. On this tab, u can end, switch to, or start a program.
Processes that are running, the Processes tab shows information about the processes running on computer.
The Performance tab displays a dynamic overview of computer performance as:
graphs for CPU and memory usage, totals for the number of handles, threads, and processes running on your computer and totals, in kilobytes, for physical, kernel, and commit memory.
The Networking tab displays a graphical representation of network performance.
Remember, networking tab is displayed only if a network card is present.
The Users tab displays users who can access this computer, and session status and names. Client Name specifies the name of the client computer using the session, if applicable.
For more Information about <a href="http://support.microsoft.com/kb/323527">TroubleShoot-Guide</a>