I helped a friend put one on a 70 Charger a couple of months ago. Wasn't to bad of a job, and it came out looking great. Just take some time planning and have lots of patience. While you might be able to do it alone, I would advise getting at least one other person to help, but two would be better, as it takes a couple of people pulling and stretching the vinyl, and another to squeegee it down.
Look on YouTube, there are lots of videos showing how to do it, and almost everyone has their own method.