The CMM can be configured as an H.323 GW, and it can be connected to a SIP proxy, but I'd stick to H.323 as the CMM EoL is on june 2014, see:
http://www.cisco.com/en/US/docs/ios/12_3/12_3x/12_3xy/archive/gtcmm.html#wp1168381
http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/services-modules/end_of_life_notice_c51-495784.html
HTH
Chris