When I quit work, we set up a budget and now live by it. We use Apple Budget software, which is set up with literally envelopes that you label (mortgage, cars, gas, groceries, etc.) and can automatically distribute money in each envelope each month. Basically, its just like what dh's dad did with paper and envelopes and cash, but on the computer!
It has saved us. My dh is mainly responsible, but we also sit down together every couple of weeks and make sure all reciepts are entered.
Its actually kind of fun - we put ds to bed, grab a few beers, enter reciepts and joke about how poor we are. BUT, it feels so good to at least know where we are financially. And this way we don't overspend.
My dh laughs that he knows the quickest way for him to get lucky is to work on the budget.
(Oh, and oooh and aaah over "my" cloth diapers!)