Thanks to arn from MacRumours for the heads up. MobileMe, an incoming .mac replacement has mentioned both Mac OS X 10.5.4 and iTunes 7.7 in it's Terms of Service System Requirements. iTunes 7.7 is also a system requirement for the newly announced iPhone 3G, found in its Tech Specs. No details as of yet, but I am guessing the OS X update will be support for MobileMe (plus bug fixes, as usual) and the iTunes update will have support for the new iPhone and AppStore. EDIT: Apple seeded the 10.5.4 update to developers last week.