I used a company just to run credit reports, but they also offer full tenant screening of their applications and check their references and employment, etc. They are also a collection agency. This is the one I used, but you should be able to find one wherever you live, if they don't service your area.
Credit Bureau Associates : Credit reporting and collection service
I have friends who were renting out their place for the first time and they splurged to have them do the full screening, and felt it was worth it.