Apple is rapidly seeding new versions of Mac OS X 10.6.3 to developers as they prepare for its release. The latest version was released to developers today and represents build 10D558. Changes listed are detailed by iPhone in Canada:
>> Apple Seeds Mac OS X 10.6.3 (Build 10D558) to Developers
>> Apple Seeds Mac OS X 10.6.3 (Build 10D558) to Developers