Billy B is right.
I worked in the intellectual property group of a Fortune 100 company for a while and it is a tough business. Look at the IP fight the PC had with DeWalt of thier biscuit joiners. Before using a patent attorney do a little footwork your self. Check out the patents (usually listed on the product or box) on an online patent database. The patent will usually refer to "prior art" or other similar types of inventions and will also refer to other patents. You will: 1) se if you really have a unique idea, 2) gte an idea for a workaround to differentiate your idea from others and 3) get ideas on what is happening in the field.
Scot