Ok ok, I'm only pulling your pisser mate, but in all honesty shampooing your dog is NOT good for them, no matter how it makes you feel.
If your worried about how they smell put some nice smellys out of Boots or something, but DON'T wash their vital self cleaning oils off of their skin/fur.
I go with what I said before, change their bedding regular, run them through some dewy grass, take them out in the rain, or let them have a little dip in your local waters, it will keep them clean and healthy.
If you wanna spoil ya mutts, just give em a kiss and a cuddle .