From USMLE website..
"Starting on or around August 10, 2009, a transition period will begin in which the number of items in current forms of the Step 2 Clinical Knowledge (CK) examination will change from 368 items to 352 items. Although the transition will occur quickly at many test centers, there may also be some locations where the changes take slightly longer to complete. The overall transition period will likely last approximately 6 weeks. The length of the examination day will remain unchanged. The decrease in the number of items per form will be accounted for in scoring the examination results, so that scores on new and old forms will be comparable. Because of these changes in timing, as well as modifications to the test item pool, there will be a delay in score reporting for most Step 2 CK examinations administered in the second half of August and September. The target date for reporting Step 2 CK scores for most examinees testing from August 10 through late September will be Wednesday, October 7, 2009."