I initially wrote support for Cisco SCCP devices in asterisk back in 2003 as I had got fed up with the SIP image not working too well on the 7960, and had a 7910 phone that would only work with Call Manager. The module works fairly well (certianly better than chan_skinny at the time).
This code is now being maintained at http://chan-sccp.sourceforge.net/. If you wish to use this module, download it from there - not here! The code here is just for historical reasons.
Note: The chan-sccp.sourceforge.net site is wrong - chan_sccp is not at ALL based on chan_skinny. I've asked the maintainers to update the site, but recieved not response, and it has not been changed.