Go to petsmart and buy petzyme
+1. I've used the same enzyme under a different brand name, but if you ask a pet store they can point you to whichever version they stock. That will remove odor. For visible stain, it's much like any other organic liquid stain; you may find you need to sand down and refinish the wood. I'm a firm believer in polyurethane varnishes for floors. Easy, durable, and pretty water-resistant.
It's a popular question, an the answer tends to be "buy a product designed for the purpose" and "use bleach / peroxide", a refinishing of the floor will probably be needed. Here's eHow:www.ehow.com/how_5655148_pet-odor-out-hardwood-floors.html Some other site:blog.worldvillage.com/home/taking_pet_stains_out_of_hardwood_floors.html Real experiences:www.thriftyfun.com/tf606054.tip.html L
For the odor, try rinsing it down really well with white vinegar. That worked at my old house after several commercial products failed to solve the problem. For the stains, there is a commercial product called wood bleach that works pretty well when used as directed. You can get it at places like Home Depot and Lowe's.