here is a record about how to deploy os on virtualbox under ubuntu server
http://burnz.wordpress.com/2008/09/04/how-to-setup-headless-xvm-virtualbox-on-ubuntu-server/
this is help for me,may be you too
and here is another article tell you how to use rdesktop
http://ubuntuforums.org/showthread.php?t=824710
