Firstly, I agree with the post ^above^. Making October the expiry month for QT 6 PR doesn't mean October is going to be the release date for Jaguar. Apple is merely giving itself and users time to transition from the preview version to the final version of QT 6, which will ship once the MPEG-4 licensing issues are resolved. Arguing that QT 6 PR's expiry date has anything to do with Mac OS X or Jaguar, an entirely different product, is shortsighted.
Secondly, Apple is referring to Jaguar as 10.2 internally. It might turn out to be 10.5 once we get closer to release, but at this point it's incorrect to refer to the next update as 10.5. It's safer to just use the codename, like Apple.
Thirdly, the absolute final deadline for Jaguar is August 22. Apple will most likely ship product sooner than that, since morale within the Jag team is high and development is progressing smoothly, but if things go ugly, this is the date we will see Jag at the very latest.
And finally, Apple will never, ever call the next major version number revision "Mac OS X 11.0". The X stands for Ten, and that would make it "Mac OS Ten Eleven" (Mac OS 1011). Very messy and confusing. I'm willing to bet that Apple either moves back to Arabic numbering from the (very ugly and confusing) Roman numerals, or comes up with an entirely new versioning scheme altogether.