When I visit one of the following pages, Webkit freezes with no CPU usage: http://www.youtube.com/ (while the page is building up) http://code.google.com/speed/ (even before the page is shown) It happened on a few other pages, too, I can try to find more of them if that is helpful. I suspect flash, as it seemed to be what those pages have in common. I already tried reinstalling flash to fix it, but it didn't help anything. I am using 532.0+ (http://webkit.org/quality/bugwriting.html says) and Snow Leopard 10.6. If I can do anything to help you (run a debug build or compile it or something) just tell me.
Created attachment 34939 [details] crash report after trying to visit http://code.google.com/speed/
It is not appropriate to file bug reports against software that is available only under NDA in a public forum such as this. Bug reports against pre-release Apple software should be reported to Apple via the usual channels.