You didn't mention which version of Eclipse you are using, but others have already posted good answers for modern versions of Eclipse. Unfortunately one of my legacy projects requires Eclipse Europa; the old EGit project homepage states the following:
The plugin only works on Eclipse 3.4 (Ganymede) or newer. Eclipse 3.3 (Europa) is not supported anymore. Since the plugin is still very much work-in-progress we want to take advantage of new platforms features to facilitate progress.
So I guess I'm SOL - back to the graphical GitHub client for me! Lucky it's a legacy project.