Jeffery Hicks (PowerShell MVP) has just recently written a power shell command call Get-GPOBackup to address and issues with managing GPO backups.
The GroupPolicy module from Microsoft offers a great deal of functionality from a command line. In terms of regular maintenance or administration it is pretty hard to beat, especially if you have 100s or 1000s of GPOs. When you have such a large number, backing them up is critical and easy to accomplish with the Backup-GPO cmdlet. However, if you want to restore or import from a backup, you have to resort to the graphical Group Policy Managment Console. I couldn’t find any way to manage GPO backups from PowerShell so I wrote my own.
Full explanation of the command can be found on his blog @ http://jdhitsolutions.com/blog/2011/05/get-gpo-backup/ as well as a link to download the command.