Even though I do the bulk of my grocery shopping on a monthly basis, I still try to save a little of my grocery money to use towards the end of the month on great deals that come up, especially meats and produce.
I have been using the Sunday Savers site to check the weekly specials for those store circulars that I don't receive in my mailbox each week. They have a ton of stores listed and you can click on whichever ones you frequent and see this weeks specials. I use it to check specials for the stores that I don't normally shop at, but are known to run really great specials on meats, like Harris Teeter. Having it all online also helps to eliminate some of the paper piles around the house.