"As of today, nearly 10 billion apps have been downloaded from the App Store worldwide. Which is almost as amazing as the apps themselves," Apple said on its website Friday. "So we want to say thanks. Download the 10 billionth app, and you could win a US $10,000 iTunes Gift Card. Just visit the App Store, and download what could be your best app yet."

Don't have an iPhone? Fear not, you don't have to buy an app to win the grand prize (though why you'd want $10,000 in iTunes credits if you don't have an iPhone is beyond me, unless you're just that into music). You can simply to win. However, to win the contest that way will take some razor sharp timing--only a form is sold can win.

If you really want $10,000 in iTunes store credit, there are some additional things you should know. You must be older than 13 years old and a legal resident in a country with an Apple App Store. Only 25 entries per day can be filed by a person, iTunes account holder, or email address. And you can't use any automated means to repeatedly enter the contest, or to exceed the daily limits.

Apple's App Store has some 300,000 apps in its inventory. That's significantly more than its main competitor, the Google Android Marketplace, which has about 100,000 apps (although, to be fair, Apple's store has been around longer).