You don't have to pay taxes on all of the unemployment benefits you received in 2009. In fact, $2,400 of the benefits are exempt from taxation. If you're married and both of you were unemployed, the exempt amount may be doubled. There's a possibility that you'll owe a healthy amount of taxes if you weren't making estimated taxes. Recruit some help to try and reduce the amount you owe so it's less than $1,000, and you won't face penalties in addition to your outstanding bill.