Although non-competes are essentially unenforceable in California, the protection of Trade Secrets is enforceable. It comes down to how your NDA is worded.

If you are truly worried about confidentiality then copyright registration may not be wise since they are public record. Unfortunately, the correct strategy to what you are doing depends on your specific situation so I can't give you a solid answer.

As a Franchise Attorney I can say you don't want to use copyright protection - it doesn't protect an idea. As the other attorney mentions, trade secret is the best route. Only disclose ideas on a need-to-know basis and always use a well-drafted NDA. Consult with a good business or franchise attorney in your area for specific advice.

Mr. Franchise - Kevin B. Murphy, B.S., M.B.A., J.D.

Franchise Foundations, a Professional Corporation

In my opinion, Mr. Murphy's answer is the more useful of those you've received so far. A business plan can be copyrighted, but the copyright wouldn't prevent anyone from using the ideas prevented in their own business. All a copyright does is prevent others from copying the words you wrote down. Any thoughts behind the words are NOT protected by copyright.

You can only patent a process, method, device, or compound, etc., not a business idea. I disagree that non-compete's are not effective in California. They are not effective as to employees generally, but they can be quite effective in partnerships and other business arrangements if prepared properly. The core of any protection of your ideas, however, is going to be well drafted non-disclosure and trade secret preservation documentation. If you really have business ideas that are that valuable, you should invest in forming a relationship with a good business attorney, rather than looking for internet Q&A advice.