If you're going to raise money by taking in co-owners, the first thing you'll need to decide is whether to structure your business as a general partnership, a corporation, a limited liability company, or a limited partnership. There are advantages and disadvantages to each of these types of business organizations, so be sure to research your choice thoroughly.
In addition, depending on how many investors you take in and how much money you raise, you may need to comply with federal and state securities laws.
To learn more about these issues, read Raising Money Through Equity Investments.
Nolo's The Small Business Start-Up Kit: A Step-by-Step Legal Guide, by Peri Pakroo (Nolo), is a user-friendly guide that shows you how to launch a business quickly, easily and with confidence.