Exporting Active Directory accounts

Does anyone know if there is a way to export (and reimport) AD user accounts and possibly GPOs to a file?

At the moment I just have a single domain running, but I want to completely restructure and rebuild the tree. I tried using the domain rename util, but with only having a single domain, it didn’t seem to want to work (probably because when I created this domain I didn’t really have a clue, and something probably isn’t right). So basically I want to start again, but without re-keying about 600 user accounts.

Any suggestions?

Thanks,

Si