Answer by Adam Lerman for How do I change the default location for a users home directory in Vista?

I have been told you can to this by:
1) Open 2 Windows explorer windows (one to the new drive, one to c:\USERS)
2) create new folder to store information on the new drive
3) right click and drag the USERNAME folder to the new folder. When the right click menu pops up, click on "Move".

To see if it worked click start, documents then click on empty space in the address bar to see if it says NewDrive:\NewFolder\USERNAME\Documents