At least 50% of the new jobs out there are at small companies, not large ones (see the U.S. Department of Labor Bureau of Labor Statistics if you don’t beleive me). But how do you find small companies? The best way I’ve found it to use a database, like Referenceusa.com or Hoovers.com. Most local libraries will allow free access to one or more of these.
Look up any company you know of that you’d like to work for, then find other companies that do the same type of work (ie, have the same SIC code). You’d be amazed at how many small companies you can find this way!
And if you need more info on how to read SIC codes, see Navigating the North American Industry Classification System from Western Illinois University.