Often you need to redirect email for various reasons on SBS 2000. This gives you a few options as detailed below.
Redirecting a users email to an another destination (no local copy)
Use the SBS Administrators console, drill down into Active Directory Users and Computer > Users. Right click on the user who needs to be redirected, and select properties. Go to the Exchange General tab and select the Delivery Options button. Under the section called “Forwarding Address” select the user you wish to forward this users mail to. If the user is an external mailbox, then you will need to create a Contact under ADUC first.
Redirecting a users email to an another destination (leaving a local copy)
Do the same as above, except tick the box “Deliver messages to both forwarding address and mailbox”