Cleaning up Exchange 2000/2003 administrative groups - Do not delete the admin group that holds the public folders
For you early adopters out there that are migrating to Exchange Server 2007. When you get your last Exchange 2000/2003 server removed from your organization, you can remove the last routing groups and you can remove some of the administrative groups that held Exchange 2000/2003 servers. But do not, under any circumstances, remove the administrative group that hold the link to the public folder hierarchy. This is usually the First Administrative Group.
If you remove the administrative group that holds the public folder hierarchy, public folders will stop working for all clients. And you will spend several hours on the phone with Microsoft PSS trying to get this fixed.