NATURE'S MIRACLE stain and odor remover, works AWESOME! According to the container it's guaranteed to work or money back. I can vouch that it has gotten rid of MANY smells in mine and friends vehicles. It's an enzyme based cleaner that breaks down the stuff not covers it up. Febreeze is OK, Laundry sheets to perfumy and just a cover up mask. Between Kids and Pets here's some of what I've used it on and cars smells clean again in a couple days:
Vomit (both kids and pets)
Chocolate milk (a couple days later in the sun)
Cat Urine (I think this was possibly the worst thing I've ever had in a closed car in summer!)
Baby Formula (smells rancid before it sits)
Unknown stench sources ( just sprayed real heavy everything in friends minivan, ceiling, seats, carpets) Took 2 applications 1 week apart but was good afterward.
You can download this from Autopia.com
http://autopia-carcare.com/freeguide.html which has some great info especially on cleaning stains smells. He recommends "Kids and Pets Brand Stain and Odor Remover" (same as Natures miracle from what I can tell) but I couldn't find it anywhere.