Removing duplicate files/folders on Windows Server 2003

In addition to my Linux work, I have recently begun administering a Windows Server 2003. There are many duplicate files and folders on the 2 TB raid array. A Google search turned up some freeware/shareware for cleaning up files, but it was mainly targeted for XP and Vista. Any suggestions for an approach I could use to remove duplicate files and folders safely?

Also, any suggestions on websites or material to come to speed quickly on Windows Server?