Post-Bac programs are for people who are not on the certification track as undergrads, but who ultimately want to teach in public schools and want to be certified. These programs usually combine some type of mentored teaching experience with a master's program.
If you don't want to pursue certification, or want to try teaching before making the commitment to a master's program, here some good sites to explore for job openings/job placement:
National Association of Independent Schools (Career Center)
Cal West Educators Placement
Southern Teachers Agency
Carney Sandoe & Associates