Skinny and MGCP are different Protocols.
Skinny (SCCP) is a Cisco proprietary protocol that is loosely based on the H323 protocol. Media Gateway Control Protocol (MGCP) is an industry standard protocol.
The MGCP firmware and the SCCP firmware are both different images for the Cisco IP Phones. The SCCP ip phone software can be found here: http://www.cisco.com/cgi-bin/tablebuild.pl/ip-7900ser
And the MGCP ip phone software can be found here: http://www.cisco.com/cgi-bin/tablebuild.pl/mgcp-ip-phone7960
tm
Tim Medley, CCDP, CCNP
IPT Consultant
http://www.iptnetworkers.com