IT TOTALLY WORKS. My clothes are so much cleaner now, I don't spend time pretreating (if needed, I may just put the soap on the stain that was going in the whole load), and no big bottles to recycle. I use about a cup a load (it depends on your water hardness), and my clothes look better and feel softer and are much, much cleaner. (Especially hand towels that certain short people dry their hands with after "washing the paint off". You know where most of that paint goes, right? Also, crawler pants with brown knees that didn't come clean no matter how much I pretreated or soaked in Oxyclean--now, they look new again after one wash.)
So, if you're crazy, too, give it a try. It really is worth 71 cents and the 10 minutes of your time.
Go here for the recipe. (Thanks, Crystal!)
Note: using my Microplane grater works best for the soap, it melts faster.