Do I owe an friend if he tells me about an idea but I create it?

Whether your friend has a claim against you or the business depends on a lot of facts. Was what he disclosed his confidential information and did you agree to keep it confidential? Was his idea a trade secret? Were you and your friend in business together when he told you about the idea? If your friend did not have a patent or other protection, he may still try to claim it was a trade secret. If you were in business together, he may claim that you breached a fiduciary duty to the business if you want to use the idea yourself. In fact, this week a lawsuit was filed against Pinterest by someone who claimed it was his idea and someone took it. These types of situations are extremely fact dependent and you should talk to a lawyer if you are concerned.