In a surprise to everyone involved, for the first hour or so, if you downloaded the sampler just by submitting an email address, you were given a download that was much larger than the same five-track sampler you'd get if you'd pre-ordered a CD, BluRay, or vinyl. It turned out that the freebie sampler was initially distributed in the rather obscure, but backwards compatible MP3HD format, wherein each MP3 file contained a lossy MP3 that various devices could playback, and a lossless audio file that you can play with a Winamp plugin, or a crappy proprietary player. This was quickly rectified, and the regular MP3 download took the place of the MP3HD download.
The internet never forgets though, 150+mb MP3HD download is available on Dropbox courtesy ihatecrayons. Get while the getting is good.
And finally, a sixth song from the soundtrack (the opening track) can be heard on The official website for The Social Network - Originally, the background for the site was a version of "Hand Covers Bruise" with no piano, but this weekend, the track got changed out with the piano version.