We have many Exchange Server 5.5 sites, and we'd like to consolidate the small sites with our primary site. We can't use the Tools, Move Mailbox command, so what's the best way to move users?

In this case, you must use the Exmerge utility to move users. However, the better question to ask might be whether you can get away with moving servers between sites, instead of just the users. With Exmerge, your users will lose rules and other useful data that can't be stored in a Personal Folders Store (.pst) file. Moving the server with the Move Server Wizard (MSW) will let you keep all the users and their data intact. The MSW is more complex to use, but you can cheat: For each small site, first move all users to one server within the site, then use MSW to move that server.