There a couple of different people/groups currently working on different 'verse maps that I know of, and it's gonna be fun watching them get sorted out. But in the meantime Josh Awtry of the incredible FireflyRPG site — where all the extra stuff you need to make your Serenity RPG amazing are there, for free — has produced a couple of great ones.
Shown above is the new Habitable Worlds map, depicting some of the notable worlds in the Core, Border, and Rim areas, with details. Even more astounding to me is the Astral Navigation chart to help you figure out how long it'll take for your characters to get from here to there in a moving universe. That's one you'll want to have printed as a poster, it's that good. And, like everything else at FireflyRPG, it's free!