TonyH a Technical Marketing Engineer for CME at Cisco passed along the attached document on how to configure Call Manager Express to use SIP phones. What a great resource! Thanks Tony.
Click Here for the CME– SIP Implementation Guide version 3 in PDF format.
Although the guide shows how to configure Cisco SIP Phones you can configure 3rd party SIP phone sto work with Call Manager Express as well. You just need to remember to purchase a seat license for each phone to do it legally :)