The script is already placed in systemroot\system32 on Windows Server 2003 so simply go to your Command Prompt and type in iisapp.vbs (the .vbs is optional) and you'll have an instant list of all the App Pool information you've always wanted to know. You may need to type cscript iisapp.vbs instead if CScript isn't your default WSH script host.
By default IIS names the app pool the same as the website name. If you name the website the same as the domain name of the website you're hosting you can use the old iisapp.vbs (from Windows 2003) to do a PID to web application mapping.
On a 64-bit Windows 2003 Server, you cannot run worker processes in both 32-bit mode and as well as 64 bit mode. On machines that run IIS 7 such as Windows Vista or Windows 2008 server, you can configure IIS to run either a 32-bit application or a 64-bit application. More information about enabling both 32-bit and 64-bit is described at:
Constrained and Unconstrained DelegationKerberos delegation on Windows 2000 Server is unconstrained. Servers that are configured for delegation in Active Directory can access any network resources or any computer on the network while using the impersonated user's security context. This represents a potential security threat, particularly if the Web server is compromised by a malicious user.To address this security issue, Windows Server 2003 introduces constrained delegation. This enables administrators to specify exactly which services another server or domain account can access when using an impersonated user's security context.For more info, Visit -us/library/aa480475.aspx 2b1af7f3a8