It doesn't appear to be available for self-hosted sites as of yet or it would be listed over at http://wordpress.ORG/extend/themes/ .
You can download the wordpress.COM version, but in my experience you end up spending a good bit of time trying to get it to work right since the themes here are different from self-hosted with coding to support the unique features and restrictions here.
https://wpcom-themes.svn.automattic.com/
If you decide to go that way, you will have to download all the files and folders for the theme and then manually upload theme via FTP to /wp-content/themes/ .
Do know that you will be on your own mostly with this project since we don't have any experience with the self-hosted software, and the people at the wordpress.ORG forums might be a little reluctant to jump into converting a wordpress.COM theme.