Looking back on that revelation about European journalist not being shipped to London to watch the Keynote, we've come to the conclusion that there's going to be only a few hardware items released on Tuesday. Why? Because if there were new hardware—MacBooks, updated Mac Minis, new Cinema Displays—the Europeans would be in on it too.
Of course, this is just conjecture, and doesn't quite mesh with some other info we've seen.
Some more developments have popped up as well, like an upcoming iChat update. The support page was updated yesterday, and notes:
This update renews the .Mac certificate required by iChat for encrypting text, audio, and video conferences.
This document will be updated as more information becomes available.
Would Apple release an iChat update alone? To us that points to two possibilities. Leopard being revealed, which is unlikely, or a new iSight camera with new functionality. This counts as new hardware, which kinda strains what we said before.
Then there's iWork and iLife apps, which were seen on Amazon for a short time, leading everyone to believe that the new revisions are coming Tuesday.
So in short, we think there's US-centric items being revealed Tuesday, such as new iTunes Movie store content, the iPhone, possibly an new iPod, and release date announcements of Leopard.