Thanks Tracerace for putting together this tutorial! I have a few tips to add, if you don't mind.
-Lye can be bought at Lowes or Home Depot. Red Devil unfortunately stopped selling their pure lye, but I use lye from a company called Roebic. Here's a link to the image: http://www.make-biodiesel.org/catalyst/images/roebic.jpg
-If you decide to use a PVC pipe as a mold, be sure to either line it with freezer paper, or put vaseline on it liberally. If you don't (or don't put enough), the soap gets stuck, and you start saying really bad words- ask me how I know. If you do have stuck soap, freeze it overnight, and the next day run warm water over the pipe, and bang away until the soap comes out.
-And if you're wondering what to do with a batch of unscented soap, try your hand at either making laundry soap, or rebatching the soap. It's all about experimentation, which why soapmaking is so fun!