I use
www.centsible.net. I'm on their paid test drive notification list as well, and I can say I wish they'd send out emails more often than they do.
They have a page on
printable grocery coupons that has links to pretty much every store I've ever heard of. I like their
red hot deals page too because it lets you know if something is really a coupon or not. If its not a coupon you can usually combine it with other offers (like coupons).
You might want to give them a try? I don't know if you're looking for printable grocery coupons specifically or online coupon codes, but they have both. Doesn't this site have coupon codes too?