Wanted to add that there is another product that works very well with stains, odors, and actually removes the scent that they are attracted to and keep going back to. It is called "GET SERIOUS", and I used it for Charlie. He never went back to the same spot and shortly after he was completely potty trained. It works so great and even gets out old stains. Petsmart carries it.
Here is the website if anyone wants to check it out: http://www.getseriousproducts.com/