Mark M , Jul 12, 2007; 10:04 a.m.
This is pretty vague Jenna. It's a little like saying "I'm cooking dinner; I've got a big pot; what are the minimum ingredients I need to make a meal?"
The minimum lighting you need is a good window. You do a lot with a clean background, good model, and decent window light. Since you say you are just a beginner, I'm assuming this is not a job, but rather a learning experience and that your model will be patient and willing to let you experiment. I suggest starting slowly: one light, a softbox, and a reflector. This is pretty hard to screw up and you will learn a lot--especially since you will get quick feedback from the digital camera. Move the light around: try different angles, move it close and far, and take notes. If you expect to have a lot of time with your model, rent two or three lights (either a few monolights, or a pack with three heads) and as the day goes on try lighting the background and adding fill. Make sure you get all the little things like stands and a flash meter--the rental shop will certainly be willing to help you out in that department. Good luck, and have fun with it.