This site is one of the few useful U.S. government websites I have encountered.   Use it to key word search in the patent database to see if someone has already patented your idea.  On the trademark side you can see if the name you want for your business has already been trademarked.    Then you can use the site to file for your patent and/or trademark your business name.  (See The Book for a good chapter on patents and trademarks)