Are you up for the chance of winning a $10,000 gift card? We can tell you how, but there's a catch. In order to enter for the chance of winning this massive gift card cash prize, you must first be an iPhone user.

Not yet an iPhone user? No problem, run along here and see if you can get yourself an iPhone 5 in time.

Now, for those who are already iPhone users, the Apple iTunes App Store is homing in on 50 billion downloads, a huge achievement when you consider that last March, the App Store was at 25 billion downloads. According to Apple, the person who downloads the 50-billionth app will get a $10,000 iTunes gift card, Furthermore, the first 50 folks who purchase an application immediately after the App Store achieves 50 billion downloads, will get a $500 gift card.

One thing to note: these gift cards will not allow you to purchase Apple hardware, only content from the iTunes Store.

The Rules according to Apple:

Prizes. One (1) First Prize Winner will receive one (1) Gift Card for credit in an amount equal to USD $10,000, and fifty (50) Additional Prize Winners will each receive one (1) Gift Card for credit in an amount equal to USD $500, redeemable in the iTunes Store, App Store, and iBookstore, as available in the country in which the applicable winner is located. Total US Retail Value of all prizes is $35,000.00.

In some countries, iTunes only supports purchase of music, apps and electronic books. If the winner should come from one of those countries, this person would probably end up being very angry.