Thanks for your help. There is some very good "down-home" advice about getting rid of the smell. Humane Wildlife is coming this afternoon and will assess the situation. I suspect, after reading your literature, that there is a family under the porch.
I also appreciated the Living Green section on your website, especially the info about cutting down on toilet flow. UNIS should publicize itself a bit more - I am sure others would appreciate these tips too.
Gaye & Peter Gruner