Go to the following link and click your CCM version.
http://www.cisco.com/kobayashi/sw-center/sw-voice.shtml
You can click Cisco IP Telephony Operating System, SQL Server, Security Updates for a list of supported OS, SQL, and security updates or go here:
http://www.cisco.com/univercd/cc/td/doc/product/voice/c_callmg/osbios.htm
These updates can be downloaded by clicking Download Operating System, BIOS Updates and CallManager Cryptographic Software or go here:
http://www.cisco.com/cgi-bin/tablebuild.pl/cmva-3des
Also, from the download page for your CCM version, you will see version upgrades, service releases, device packs, etc. You will need to read the release notes to determine prerequisites, etc.
You will need a CCO login to access the software center.
Hope this helps. If so, please rate the post.
Brandon