Audit Logon/Logoff events

HI..

Can anybody tell me how to get only the user logon/logoff events on a win2k domain network.
I have taken all necessary steps to setup and infact getting the two types of events. 1. Account Logon/Logoff. 2. Logon/logoff events under security.
These events are considerably more in number, what i feel is events are generated for each and every instance of server access.
I want to get only only two readings. User login and user logoff to report the working time of each user.
Our users work on MS ASP, MS VS.net, MS SQL constantly connected on/to the server.
Pl. specify the IDs of the events.
Please give me any solutions.

Bye and Thanks