Along with Apple’s iPhone 3G in July 2008, Apple also launched their App Store. This is the place where iPhone and iPod Touch end users can download mobile applications specifically made for the iPhone. These applications may be free or may come at a price.
Mobile software developers are able to create applications for the iPhone and then submit them to the App Store for approval. There has been some controversy over this due to Apple banning certain applications.
Google has announced that the company will host a similar app store for Android mobile operating system users. The Android app store will run slightly different than the Apple app store; Google is allowing all developers to submit their apps to be hosted without needing an approval. These apps will also be offered free or for a price determined by the developer. A beta version of the Android app store will contain only free applications, and will be available on the first Android based phones.
To upload an application to the Android app store, a developed needs only to register with the store. Then he or she will be able to upload and publish the app.
Source: Android Authority