Font-awesome CSS
Font Awesome is fully open source and is GPL friendly. You can use it for commercial projects, open source projects, or really just about whatever you want.
Attribution is no longer required as of Font Awesome 3.0 but is much appreciated: "Font Awesome by Dave Gandy - http://fontawesome.io".
Font License
Applies to all desktop and webfont files in the following directory: font-awesome/fonts/.
License: SIL OFL 1.1
URL: http://scripts.sil.org/OFL
Code License
Applies to all CSS and LESS files in the following directories: font-awesome/css/, font-awesome/less/, and font-awesome/scss/.
License: MIT License
URL: http://opensource.org/licenses/mit-license.html
Documentation License
Applies to all Font Awesome project files that are not a part of the Font or Code licenses.
License: CC BY 3.0