I use Excel.
A good tip for first starting a budget: Keep track of every $ you spend for a month or two... keep receipts and bills; write down anything for which you don't get a receipt. You'll get a real idea of where all your money is going and exactly how much you're spending. (I just put all of this into a big manilla envelope, writing on the reciept what it was for if the receipt wasn't clear, and then went through them all at one time.)
Then use, those numbers to find places to easily trim your spending. Some quick ones... decrease eating out, reduce or eliminate your cable t.v. package, get rid of extras like call waiting and caller i.d. on your telephone.
Once you've made some reductions in spending, you might consider using the extra breathing room in your finances to pay off debt (I recomment the Snowball Method), increase savings for your retirement, for the kids' college, and/or save for something special.
Good Luck!