virtualbox.org

The guest and host are windows XP, The domain controller is SBS 2003.
I am needing to join this Virtual machine to the Domain and am not real sure how to do it.
Could someone help me?

The simplest method is to use bridged networking so that the vm behaves just like the host (or an other machine on the LAN). The vm will get its network config from DHCP and look like any other domain member to the DC.