Is their own site well designed? Do they do great work for their clients? Can they help bring publicity to you?

 These are all questions you need to ask yourself. Start crossing out the companies which you don't have a good feeling about, until you're left with three. Contact the best three. At this point you should have some pretty good people on your list. Call or email to let them know that you're interested in having them design a site for you. Tell them in detail what you want and expect from a web site. You should not have to wait more than a week for a response from each of them. Realize that these companies are now doing work on your behalf for no pay. Typically a firm will spend 1 hour per $1,000 dollars preparing a response in order to get your business. You should not expect them to do any "free" design work or give you lots of ideas. If you show that you value their time and creativity, the relationship will get off on the right foot.