Mac Rumors is reporting that Apple has seeded a new build of Mac OS X 10.5 Leopard (build 9A283, for those keeping track) to Select and Premiere ADC members, the first major seed since preview versions were given to the devs at WWDC 2006 in August. Interestingly, this build is meant to be a fresh install - not simply an upgrade over the previous version. Mac Rumors also has a roundup of at least some of the major changes from the WWDC build:
new Parental Controls preference pane for content filtering, apps, and curfews
Significant user interface changes to iCal
3D audio cues to indicate locations of items on the screen in the VoiceOver screen reader
Basic editing in Preview
I can't help but hope one of those 'significant' UI changes to iCal includes a new 'unified' look to bring it more in line with their move away from the ill-fated brushed metal.