As Mike told.. its already integrated.. MOSS has ability to fetch the presence information from Office Communicator...
Could you pelase explain what exactly do you want to acheive?
And yes.. Ensuring same SIP and email address helps in this case.
Regards,
R. Kinker
MCSE 2003 (Messaging), MCTS - LCS 2005, MCTS - OCS 2007
http://www.ocspedia.comhttp://www.itcentrics.com/LCS_Home.htm