MacRumors.com

Wired posted and then removed screenshots (Google cache) from the WWDC Developer's Build of Mac OS X Leopard.

Installation of the Leopard went smoothly on their Quad-Core Xeon Mac Pro, and their first impressions were solid:

Leopard already looks very sleek -- the reflective dock, translucent menu bar and deeper drop shadows behind active windows give the desktop more space-aged gloss. Animated behaviors like Stacks, Spaces and Cover Flow in the Finder rendered super-smoothly on our fast test system. There are new screen savers, updated remote desktop management settings and some of the core applications (Mail, Safari, iCal, etc.) have been redesigned.

The screenshots that were removed depicted iCal, Screen Sharing, and the new Screen Savers.