Internet Information Services (IIS) 6.0 generates events in Event Viewer so that you can verify the performance of IIS. Event Viewer tracks the following: error events, warning events, and informational events. The logs in Event Viewer provide an audited record of all services and processes in the Microsoft® Windows® Server 2003 operating system, such as logon and connection times.
WWW Service Worker Process Events
WWW Service Performance Counter Events