I want to start this off by saying that the Beta has not yet begun. This was leaked from an ex-Blizzard employee, who must've been in the Beta prior to it beginning.
Now, normally we don't post leaks and the like, but I figure with Beta fever and the lack of information from the Webcast this morning, you'd all love to see some cool stuff... That in mind, he's posted up a video (as seen below) as well as a gallery.
Now, you may notice if you pause at just the right moment that Skill Videos are displayed on the character creation screens... Don't they look familiar? It also explains why the videos had no sound to them. Either the sound is added programmatically inside D3, or there is just no sound on them period. Regardless, those videos were extracted from the Beta client and leaked to the web, they were not supposed to be used for any Community posts or game guides, or anything else that we may have speculated on.
It's also worth mentioning that two new D3 Beta-only subforums have been added to the Community Site, the Feedback Forum and the Bug Report Forums.