Is is possible to replace the CD drive in a 17" macbook Pro with a SSD/second HD?
System Profiler is an application that will show you hardware information to determine which bus the CD drive is connected. Once you know your hardware specifications, you can shop better. 

Check MCE optibay and OWC Data Doubler for housings that work physically with SATA connectors. Also check Remiel's article on the issues you might face moving to an SSD / HD combination.