While during regular maintenance on one of my IIS6 boxes, I noticed a worker process (w3wp.exe) that was totally out of control. The process was up to almost 700megs! Immediately, I needed to know which application pool this worker process was related too but I could not find out how to get this info from the system monitor tools in Windows Server 2003. Thankfully, there is a dos VBS located in the System32 folder that you can use to lookup which worker process PID belongs to which application pool.

To use this simple VBS, navigate via dos to your C:\Windows\System32\ folder and run cscript iisapp.vbs

Now that you know which application pool is causing the problem, you can dig into your application to find out what is going wrong.