Did the change in his behaviour coincide with any other dramatic change in his environment like a human moving in or out of the house or another cat arriving?

...I take it from your comments that Scooter has been declawed? If so, when did this happen in relation to his peeing around the house?

Have you tried retraining him? As horrid as it may seem literally rubbing his nose in it followed up by placing him in his cat box and some stern dissaproving words has always done wonders for me (or should I say my cats ).