Thanks to Your Coupon Buddy, I found a coupon for $5 off a $25 dollar purchase at Petco. It is limited to in stores only and you must use your P.A.L.S card. It's alos limited to one coupon per household.
Here is the link.
Offer expires 2/15/2009, this would be a great way to purchase Science diet for their 3 bag challenge and earn bags for your free bag with your P.A.L.S card.