This is what we are doing. We had an Exchange 5.5 in a Windows 2000 Domain. Moving this to Exhcange 2000. INStall the admin utils for Exchange 2000 on an AD Server. Then use "Active Directories USers & Computers to move mailboxes. When right-clicking on any user you have an option for "Exchange Tasks" one of them is an option to move their mailboxes. This is quick and very easy. WSwell, it was for us.