I am in need of a detailed difference between scorm 2004 2nd and 3rd. Can anybody point me to some good references?
Here is a good reference on the evolution of SCORM.
SCORM 2004 3rd Edition is mostly a tightening of 2nd Edition to clarify some ambiguities that were discovered as people started using SCORM 2004. The big addition is some requirements around the user interface that the LMS must provide. Overall, 3rd Edition is much stabler than 2nd Edition (and 4th Edition is stabler still).
ADL published a comprehensive listing of the changes between 2nd and 3rd Editions as an "Impact Summary" document. It contains 41 pages detailing every last change between the two Editions. Enjoy!