Steve Jobs announced Leopard will be available in spring 2007 and then handed out developer pre-release OS 10.5 to the developers attending the WWDC.

This has then spawned a number of preview sites (quickly getting nailed by Apple), and a number of videos on You Tube.

One thing I've noticed are is the tabs are coming!*

* Sorry if someone else noticed this ages ago :-|

From some of the videos released on You Tube you can see that tabs are being integrated in to more apps (okay, maybe just Finder) in a consistent manner:

Check out the cool effect of dragging a tab from out of the tab bar.