I should mention that if there's anyone planning on capturing this, and has Cinemax on Demand, apparently Lucasfilm will be showing "more than a dozen special features and footage - from original concept art to the behind-the-scenes looks at the making of the saga's creatures, weaponry and more" (as per it's press release). That might be a good thing to get as well, although I have no idea whether these are entirely new featurettes or old material just re-aired.

There are also supposed to be "trailers and behind-the-scenes" content available on the Cinemax website during the airing of the films tonight (though it might stay on there longer).