Wired News has obtained a preview copy of the new Mac OS X 10.5 operating system. They installed Leopard on their test machine (a quad-core Xeon Mac Pro):

First impressions: Even though the code isn't final, 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. Firefox 2 and Photoshop CS3 both booted up just fine. We mounted a 3G iPod via Firewire with no problems. Spaces is controlled by the F8 key, so if you've been using the F-keys for Expose, the workspace manager is easy to add to your muscle memory. Spaces can also be assigned to a button on the Mighty Mouse -- super handy. We still haven't had a chance to burn a DVD, try Time Machine (which requires an external hard drive) or test many of the new features, so we're really just scratching the surface.