For a presentation I gave last saturday I made a KWin screencast showing off KDE beta 2 stuff. Quality in Youtube is rather low, but viewable (with annotations). Here you go.
And here's blib.tv (better quality & oggfile available).
edit: blip.tv is still transcoding the video to a flash-format, so you can now only view the ogg file if your system/OS is capable of viewing that format. I wouldn't know why it wouldn't be as the video format doesn't have any associated costs or royalties and has been around for years. But if it is not available for you, you just have to wait for the flash version to be ready...