Apple announced a delay of the next version of the Apple operating OS X Leopard.

In a brief note Apple blames the complexity of the upcoming iPhone as the reason for the delay of the highly anticipated Leopard.
Apple had to shift resources from the OS X developer and QA team to the iPhone team.

Much blamed Digitimes was right afterall. The broke the Leopard delay story already in March.
Apple plans to show developers a near final version of Leopard at the WWDC 07 conference in June and handout a beta copy of Leopard. The final version of OS X 10.5 would ship in October.
The Apple iPhone is still on track for the June release.
Via the Apple site.