The Missouri Regional Education Application Placement service. This is a great source for looking for jobs, especially outside the larger cities. School districts often post openings in the system, and check the system for applicants.
Advice from Beginning Teachers:
Spencer Fields -- "My only advice that I have is that the amount of time I have spent this year dealing with Classroom management is WAYYY more than what I expected. That is something I wish I knew." University of Missouri, Kansas City.