It takes a lot of confidence to label a project “awesome,” but after looking over the Font Awesome collection, I’m inclined to agree.
The project includes a set of base icons similar to the Glyphicons included with Bootstrap, plus a set of extended icons that include pictograms for external links, thumbs up/down, comments, cogs and more.
The GitHub Readme also includes full instructions for using Font Awesome with or without Bootstrap.
Font Awesome is licensed under the Creative Commons Attribution 3.0 Unported (CC BY 3.0). Developers can use and remix the fonts as much as they want, even for commercial projects, but do need to provide attribution as specified by the project. In this case, Gandy asks for a mention of the project and URL in “human-readable source code,” so dropping a mention in a project’s CSS should be acceptable.