Samsung has posted an updated video showing the American version of the Galaxy S II. It's notable that Samsung has removed the iPhone-like home button and replaced it with more Android-style controls. In the video you'll see the current version of the phone, and the new button arrangement at the very end.
Apple has loudly (and legally) complained about competing phones that have copied the look and feel of the iPhone design, and it looks like Samsung is responding by removing elements that are clearly derivative.
The U.S. version of the phone is likely to appear on August 29th.