Apple yesterday announced a huge giveaway bonanza as it approaches its one billionth iTunes sale.

Each music fan who buys a 100,000th song gets a prize - a black 4GB iPod nano and a $100 iTunes Music Card. The music lover who downloads the billionth song will receive a 20-inch iMac, a $10,000 iTunes Music Card, and ten 60GB iPods.

Apple will also launch a full music studies scholarship at one of the world's leading music colleges in the winner's name.

But how can you increase your chances of snagging those prizes? Enter iTunes Estimator.

iTunes Estimator is a small application that shows Apple's current estimates of song sales so far on iTunes. It analyses the data to offer an estimated time at which the next 100,000th track sale will take place. It updates every 5 minutes, and beeps every second for the ten seconds before that estimated sale takes place.

There are a few snags in this solution: "If Apple changes the source data format or location, this application may break," the developer warns, adding: "Some people have noted that there are discrepancies between the counter on Apple's page and the application. This is because Apple has adjusted its estimate rate to 80 per cent of the raw data calculation."

Of course, with everyone attempting to grab that prize-winning sale, sales are likely to spike - skewing all such averaging machines - whenever a prize-winning song sale is in sight.