If you are thinking about taking your business to the next level in 2011, I'd recommend checking out the Small Business Bible by Steven D. Strauss. It's not specific to photography, and in some ways that makes it a refreshing read. There are no references to which lens to buy, or what lighting kit is best. It's strictly designed to help you get a firm grasp on the actual business side of things. Legal issues, taxes, and marketing are all covered in great detail. I actually found the audio book at my local library so you may want to look there first.
Another terrific resource is the blog over at entrepreneur.com Simply subscribe to their feed for timely tips, and useful articles. You may want to start with this one about preparing an effective business plan.
I would also recommend downloading this free PDF ebook by HP SugarTone. It features a wide variety of cutting edge methods being used by small business owners all over the world.
Wishing you a Happy, Healthy and Prosperous New Year!