Charisma-Get What the Greats Have Got' is an easy and interesting book to read. Even though the authors are British, they pepper their examples with plenty of American celebrities and historical figures, so the references are pertinent.
What I really liked about the book was that it contained practical advice for improving your own interpersonal skills. Anyone, regardless of their social skill level, will find a way to improve their ability to connect with others in both large and small settings.
The book is organized so you can easily go back and re-read the portions that are most applicable to your personality and communication areas you would like to improve, and their SSF method--Story, Status, and Focus, will wok for anyone on any level.
And in addition to telling you how to better your communication skills, the authors also discuss what NOT to do for