http://www.nytimes.com/2008/03/27/business/smallbusiness/27sbiz.htm
discusses the difficulties that small business owners have in getting health coverage, especially if they have medical conditions. Here are some resources the article mentions:

http://healthinsuranceinfo.net/

http://sbsb.com/ Small Business Service Bureau

http://advocacyforpatients.org/ Advocacy for Patients With Chronic Illness, Inc.