Cisco is moving SIP into a lot of products, with an end-goal of total end-to-end support.
Unity 4.0 supports some SIP capabilities today, and you can follow the links from here to gain more information:
http://www.cisco.com/en/US/partner/about/ac123/ac114/ac173/ac222/about_cisco_packet_department09186a0080142dc9.html
and here:
http://www.cisco.com/en/US/partner/products/sw/voicesw/ps2237/prod_configuration_guide09186a00801171ed.html
As you probably are aware, most of the IP phones have supported SIP loads for quite some time. If you do a search on SIP in CCO, you'll see that SIP components are integrated and being expanded in the Cisco firewall, VPN, and IOS lines.
I can't discuss roadmap and Cisco-confidential items on NetPro, so I need to direct you to query your local account team directly to gain further access to specific information regarding the inclsusion of SIP in Cisco CallManager.
I can assure you that SIP support in Cisco CallManager is an important priority, and that you should not have to wait too long before you begin to see more SIP capabilities native to CallManager.
IP Phone Messenger shipped with CallManager 3.3 in December 3.3, which enables presence and location capability for IM to the phones, and includes support for SIP.
Good luck,
Joe
