Resizing system drive on WNT4 Server

Where I work we have one server running Windows NT4 sp6. Currently there are 2 scsi disks installed. I am planning to add a third. The dilema is in the best way to change the size of the system drive without screwing anything up. Right now it looks like this: Disk 0- drive C (system files) NTFS 1467MB, drive D (data files) NTFS 7177MB. On Disk 0 I want to take the files off drive D and store it on the new drive-I believe that should not be a problem. Then I want to wipe out drive D and make that space available to make drive C larger. What is the best way to do that?