What options are best offered to investors?

I have been planning for years and slowly working on launching my own business again. I have read many articles and I have debated on going the route of an investor but I am unsure on if I should make an offer in my business plan or if I should leave it up to discussion? Is it norm for investors to have more ownership of the company than you? I have discussed this with a friend in college and they had stated some investors request 60% ownership of your company. Is that not giving someone your idea though?

EDIT:
I have done a large amount of research and have found score.org and was informed it would be good to contact the local chamber of commerce. I'm just trying to make sure I have everything prepared and no surprises.

The amount of your company that you'll have to sell depends on the value of the company when you take the investment.

For example, if your company is worth $1 million before the investment (the pre-money valuation ), and you take an investment of $500,000, the post-money valuation will be $1.5 million (because there is now another $500,000 in the bank). Because the investor bought $500,000 worth of a $1.5m company, they now own 1/3rd of the company.

So, to figure out how much you're going to have to sell, you need to know how much the company is worth before the investment and how much investment you are taking.

Both of these figures are a matter of negotiation between you and any potential investors and will be described in the term sheet which the investor gives you when they agree to invest in your company.

All else being equal, you will want to negotiate as high a pre-money valuation as possible, because that way you give up the smallest number of shares for a given number of investment dollars.

As usual in negotiation, the stronger your negotiating position, the higher a valuation you will get. The strength of your negotiating position depends on how strongly the investor wants to do the deal, and how much competition there is to do it. The best things you can do to get a high valuation are to have a very attractive company that investors are dying to invest in, and get multiple investors lining up so there is competition to invest in your company and you can choose the best investor.

Ha, 60%?! Only if I was in an industry with an extremely high start up cost would I consider taking that much (think biotech or aerospace).

As Joel said, you want to focus on valuation and trying to get a fair estimate on that. You'll need a professional to look into it, but make sure to prove projected income as well as projected market share. You're likely to be valued at a price to earnings ratio similar to peers in your industry, as well as the potential to grow into that industry. Make sure you drop a long term plan with solid growth pattern. Investors usually invest in strong numbers run by people with vision.

Never give up a controlling stake of your business. A controlling stake means you can be fired. That's right, they can legitimately steal your product - because the contract you signed makes it possible. They can force your company into non-existence and then who owns the product? The majority investor. Think about that.