call credit-check agent
If you you never checked someone else's credit before and you are in a hurry, you can call some credit-check agents and ask them to check for you. It will cost you around $25. You can find these agents online or in the Yellow Page.
If you need to check tenants' credit all the time, you may want to sign up an online service so you can check youself. You have to sign a couple of forms before you can use it. Once it is setup, you can get someones credit report immediately 7x24.