Once you have your Octopress blog in place, you might wonder how you start contributing from another computer; either yours or a friends.
You need to setup Octopress for each computer but not from scratch. Clone your repo, switch to the source branch, then manually set up a _deploy folder and bind it to the master branch.
Setting Up an Existing Octopress Blog
$ git clone git@github.com:usr/usr.github.com.git
$ cd usr.github.com
$ git checkout source
$ mkdir _deploy
$ cd _deploy
$ git init
$ git remote add origin git@github.com:usr/usr.github.com.git
$ git pull origin master
All done. Courtesy of code.dblock.org