Five Basic Lighting Principles is a great video from Chuck Peters of Digital Juice that describes basic, 3-point lighting technique, creating/controlling the emotional impact via lighting, how to light 'difficult' subjects (e.g., people with glasses) and other useful tips.

Professional lighting gear can cost an arm and a leg, but the non-professional video enthusiast can find readily available materials and equipment to light the subject and scene inexpensively.  In Cheap Video Lighting Solutions, Tom Skowronski from videomaker provides a quick demonstration of the use of such things as work lights, China lanterns, and shower curtains to addresss the problem effectively and inexpensively.

• For key light, use a 1000 watt work light (or 2)
• 500 watts are enough for a studio interview if the subject sits close to the camera
• For a back light, use a China lantern, available at retail stores
• For diffusing the light -- i.e., making it softer -- you can use a transparent shower curtain.  Remember to keep it at a distance, because the lights may be very hot.
• For outdoor shooting, you need a reflector to reflect the sun's light.  A cheap, foil-covered windshield cover works great.  Alternatively, you can use aluminum foil, wrapped around a big piece of cardboard.  Crumple the foil for a softer reflection -- e.g., for a fill light.
• Lighting gels are used to modify a light's color.