I am going to be joining my computer to a different domain than the one it is on right now.
How can I copy my current user profile and preferences to the new user profile that will be created when I login on the new domain?
This is a list of references (in preferred order of reference).
How to copy data from a corrupted user profile to a new profile in Windows XP
Microsoft support KB811151
How do I copy one user profile to another? (Indiana Univ KB)
They also have these two interesting notes.
Note: At Indiana University, the University Information Security Office (UISO) recommends that you normally refrain from running your Windows computer as an administrator. For more, see What is the principle of least privilege?
Note: As copying one profile to another will completely overwrite the target profile, you should back up any important data before copying over a profile. It is also a good idea to test these steps on a test profile before copying over a profile in use.
In XP (possibly works like this in 2000, no promises about Vista):
To restore this into another profile, just copy the files in your backup into the other profile. Again, don't be logged into the profile you're copying into.