I use AmerUSA.com - it is both a credit & criminal check for a small fee ($30). You would need the prospective tenant's email address. They authorize you to pull the report via email, and you have it immediately.
What aspect of section 8 are you worried about? If you want to keep your tenants, you can take Shaw's advice below and just sign up with the housing people. Section 8 is the owner's choice. If you want to get rid of your section 8 tenants, I believe you just call up section 8 and tell them you don't want to have section 8 units and they take their vouchers elsewhere.... more