Here are some links, articles, and resources that may be helpful for organizing a race.

How to Organize Your First Race

Active.com has a web page with a lot of helpful links and information.

Contact Local Running Clubs

Local running clubs would also be a good place to contact. Most likely they've put on races through the club and would know what permits are needed, who can certify a course, best places for a running event course, marketing/sponsorship/etc.

Find a Timing/Race Management Company

Find a timing company/race management company in your area. These companies will handle race setup, timing, etc. for a fee.

Create a Website

A year round presence for your event is extremely important.