Loop Lighting

What you need:
Four lights
Camera and tripod
A Seamless Background
Lighting Stands (2)
Stand for overhead light (1)
Subject (1)

What To Do:

Step 1: Set up  the backdrop at a perpendicular angle to the subject.
Step 2: Put a background light facing back directly behind the subject lighting the backdrop. Set it up low and so that it it cakes a semicircle of illumination behind the subject, and have it grow gradually darker as your eye moves further away from the subject.
Step 3:  Set up the key Light 35 degrees off of the camera and tripod
Step 4: Set up the fill light 20 degrees off the the camera on the other side
Step 5: Set up the hair light, using already available overhead lights or the overhead light stand.

If using softer lights, move the lights closer to the subject.

Examples:

Bill McIntosh

Shelby Clark

Sources:
http://www.sekonic.com/whatisyourspecialty/photographer/articles/the-five-basic-portrait-lighting-setups.aspx
http://shelbyrenee20.blogspot.com/2010/11/pressure.html