Check out the Zalyn website. IMHO, it is much easier to use than the others and gets you pretty good results quickly.
I like to think of it like kayak.com for coupons. You simply enter your info and it figures out which coupons should work for you. By signing up, you can enter your membership(AAA, Costco, etc) and rewards program and it includes those coupons as well. They show a number of coupons and you can compare the discounts in batches of five at a time. They basically send your coupons over to Travelocity to see the discounted rates.
Tip: Sometimes on Travelocity, the top column says discounted but the rate is not really discounted. If you look to the right, you'll see the "undiscounted" rates for the agency and can see how much you saved. Remember to compare the total amount. It seems some coupon discounts don't change the daily rate but the total amount.