7 Minutes of Sith
Not that it will be up for long, but someone filmed what I'd describe as a 'summary' screening for Sith. It has no dialogue, with music overtop the scenes. Basically, a start-to-finish briefing.

I wouldn't say that it really had any spoilers in it. If you've watched the trailers, there's nothing in here you wouldn't expect. You get some great extended looks at Grievous, who looks positively creepy; you get a bit more of the Emperor v. Yoda and Anakin v. Obi-wan. Glimpses here and there. I've watched it about four times now.