Thanks to J.D. and his new personal finance blog Get Rich Slowly. J.D. pointed me to this easy to use free spreadsheet at PearBudget.com.
It's an all in one tool to help an individual or family to better organize their family expenses. We're doing well and the missus does a great job of keeping things in order but it's the extra expenses that we need to control better. Stick to the budget and if we're about to overspend then the expense will just have to wait until the next period.
We'll try using this one (as well as our home-rolled solution) and report back on the results later.