Here are some good business reads for indie entrepreneurs.
How to Start as An Illustrator: Authored by artist Keri Smith, this is a simple, yet rich (and full of links) guide to starting an illustration career.
Fast Company: Great magazine for business leaders.
My First Book of Business Etiquette: Owning your own business means interacting with all types of people-from managers, clients, suppliers. This book details essentials such as how to schmooze, conduct meetings, etc.
Creatively Self-Employed: This book by Kristen Fischer discusses life of the creatively self-employed-from taking the initial plunge, dealing with clients, to maintaining balance. This book shows you how to build confidence in your work, cope with rejection, and maintain a strong business.