First, see these tips on making your resume cyber-safe.
America's Job Bank
National clearinghouse for the public employment service
Bureau of Labor Statistics: (scroll down) describes for example the nature of OT jobs, working locations, job outlook, salary, etc.
Federal Government Employment Opportunities
Job-hunt
Super site of popular job resources.
Missouri employment opportunities: job-hunt.org
ShowMeJobs
Columbia Daily Tribune employment opportunities
University of Missouri-Columbia Employment Opportunities