Sometimes you need to know a service account password and don't have it. Maybe your dog ate the documentation to your dev environment. Powershell to the rescue!
PS U:\> Add-WindowsFeature Web-WMI | Format-List
PS U:\> Get-CimInstance -Namespace root/MicrosoftIISv2 -ClassName IIsApplicationPoolSetting -Property Name, WAMUserName, WAMUserPass | select Name, WAMUserName, WAMUserPass
Fun and scary.