The creators of Shank, in response to fan demand, have opted to make the soundtrack freely available. Currently, a half-dozen of thirteen total tracks can be had from the offocial site (http://shankgame.com/); all should be available around 25 August.

(source (http://www.gamespot.com/news/6274097.html))

Since this is now somewhat buried on their site, here's the link to the blog post which contains both mp3 and flac versions: All Your Soundtracks | The Official Shank 2 Blog (http://www.shankgame.com/all-your-soundtracks/)

Thank you.