We're using Exchange and have a large number of distribution groups we need to mail enable. Is there a way to mail-enable all of the groups at once?
Sure. There is a cmdlet you can use:
get-group -organizationalunit OU_Name | enable-distributiongroup
This cmdlet finds all of the universal groups within the organizational unit and enables them as distribution groups. It's supported by Exchange 2007 and up.
More Information
Get-Group in TechNet's Library has more information Get-Group