Edit: Apparently the sass file was removed from the latest versions of Font-Awesome... You can still download the sass file from GitHub here
- Download Font Awesome source
- Take the file sass/font-awesome.sass and put it in your octopress sass folder
- Rename it to _font-awesome.sass
- Create a directory 'octopress/source/font' and put the 4 font files there (ttf, svg, eot and woff).
- In your stylesheet (sass/screen.scss):
@import font-awesome