I would suggest EMS Employment 7 topics down from main this forum interface. I think EMS1.com has job postings, along with JEMS, EMS world, career builder, monster, 911 hot jobs, craigslist. Its free to view all of them not sure about posting them as an employer
Craigslist.com is very easy to use and free. The company that I was hired at said that they received about 20 apps a day in the first few days using craigslist.