Jason Anderson has posted this review of the present state of Lion on YouTube. It runs fast, so use Quicktime back/forth controls to review the segments -- and it helps to run it at full screen size.
Apple Insider's web site has been collecting information about Lion (10.7) and has collated it (with samples, videos and other non-geeky stuff) here: Inside Lion previews.
Now if these aren't a topic for discussion what is? ;-)
Euan Williams 