Amy Herold has a quick script to find which Active Directory users are in particular AD groups:
There was something that popped up today that called for a PowerShell script and the Get-ADGroupMember cmdlet – get a list of users from a list of groups. Some users are in there more than once so this needs to be a distinct list, unless you are into manually cleaning up things like this, and then I will be sad for you. Because that is kinda sad.
I originally wrote a script with two arrays (one for the initial list and one for the de-duped list of users), but even though this is quick and dirty, that was a little too dirty. Enter the Group-Object cmdlet – it takes this list of names and groups them. No black magic this time. Just a cmdlet, that comes baked into PowerShell giving me what I need.
Click through for the script.