How to Run a Service with optimal Security?

I am using WindowsXP
I installed Apache Tomcat Servlet container as a service. It�s user guide says " For optimal security, the service should be run as a separate user, with reduced permissions (see the Windows Services administration tool and its documentation). "
So I went to Control Panel-->Administrative Tools-->Services and selected and right clicked on Tomcat which was now installed to log on as a Local System service and selected properties.
From Properties-->Log On tab-->selected this account -->clicked the Browse Button-->Select user Dialog Box-->Advanced-->clicked the find user Button-->Selected Network service

And came back to the log on tab of properties and entered a password and clicked OK button
Then restarted Tomcat. But when I entered http://localhost:8080 in IE it keeps on waiting, the Tomcat home page never gets displayed. How can I run Tomcat under the Network Service Account? How can I find out the privileges allowed under the Network Service Account?

When I am logged on as a administrator or in any other account, Is it possible to start a Service or another program which has rights granted under another account?

I never created a Network Service or local service Account are they default accounts?
How can I create an account which has adequate privileges to use a service with ensuring optimal security?

The above described procedure is from the "To configure how a service is started" title which is Under the Services node of the Microsoft management Console which appears when the help menu for the Services Window is clicked.

Help!
Regards Varuna

You need to create a new Windows user Account (not Administrator), and assign that use to the Service.

The Network Service- and Local System Accounts are used by the Windows OS.