How many businesses are you talking about? If it is a large amount, a "Links" page is usually used, although I find this kind of content display kind of annoying. If it is a few, just create a sidebar or footer with your sponsors in it. You can rotate the sponsors on page loads to increase white space.
Why don't you refer us to something you have seen and then we can point you in the right direction.
Stop worrying about links unless they provide associative content. Worry about content. Spend your time on unique content, create the content in such a way that a scraper cannot duplicate it easily. Unique content will always increase SEO.