UPDATE: Link Fixed/Changed
OK, click below for some Widescreen- Full Frame (Open Matte) screencap comparisons!
As I mentioned the Open Matte transfer does occasionally (ever so slightly) crop the sides (example = Jack in stream), but for the most part on the Full Frame DVD you'll see more picture above and especially below the normal "letterbox" ratio. Case in point, check out the full frame screencap with Jack leaning on his truck...oh my. This also holds true for the tent scenes, the motel scene etc, etc.
It also bares repeating, "more picture is not always better" as it does alter the film's artistic/visual composition...I see the Full Frame DVD as a "bonus" viewing experience to the definitive Widescreen version. The Open Matte (for standard TV's) certainly draws you into the "frame" more, and thankfully in this case, that's a nice alternative.
Updated: Here's the link that will take you to directly to the start (several pages) of Screencap Comparisons on the DC message board.
http://davecullen.com/forum/index.php?topic=4716.msg154880#msg154880