When debugging WebParts not knowing which w3wp process to attatch to has always bugged me. Thankfully ASPalliance has this article to show you how to identify the w3wp process for an app pool.
The gist of it is.
Shipping with Windows 2003 is a vbscript named iisapp.vbs.
running "cscript iisapp.vbs" from the command prompt displays list of w3wp processes running, its process id, and the app pool it belogns to.
tags: SharePoint, IIS6, Windows 2003, WebParts, Debugging, Application Pool, Attatching
Cross-posted from tariqayad.com