iisapp equivalent in Powershell

Hello,

We're in the process of upgrading our web servers from Windows 2003 to Windows 2008R2 and I'm learning Powershell in the process. I wanted to know if there is an equivalent command to iisapp, as there was in Windows 2003, for Powershell. I want to be able to get the process ID's for all worker processes.

Appreciate any help.

Thank You.