Yesterday a number of screenshots (more screenshots, pipeline screenshot) purporting to be from a developer's release of Mac OS X 10.4 made their way onto the internet.
While sources have been unable to directly confirm the validity of the images posted, we have been able to get reliable confirmation that many of the concepts -- including the Safari RSS implementation as well as the Konfabulator-like widget plug in system -- should find their way into Mac OS X 10.4.
Mac OS X 10.4 (Tiger) will be previewed this next week at Apple's World Wide Developer's Conference.
Update: ThinkSecret reports that one reliable source confirms the screenshots are genuine.
Update 2: Images removed at request of Apple Legal.