Android Market
It almost goes without saying that your need to post your app to Google's Android Market. It's not required[md]you could post your app elsewhere and not on the Android Market. But this is the flagship of Android app stores and will serve as a key launch point for your app. Post your app to this store to get maximum exposure and improve the chances that your app will be reviewed.
The Android Market really has come a long way in helping developers to market their apps. In fact, the Android Market has some benefits and features not found on Apple's App Store, which set the original standard for selling mobile apps. For example, the Android Market provides an option to include a video of your app. This is a powerful feature that shouldn't be overlooked when marketing your app. Seeing is believing, and a video helps the potential buyer to experience your app and understand its use.
The Android Market also does a nice job of organizing content on the product page for each app. Information is organized into tabs (Overview, User Reviews, What's New, and Permissions) that allow the visitor to click around and easily learn more about the app. For web users, the Android Market is easily accessible with any web browser, and the selected app is displayed prominently at the top of the screen with the app's icon and header graphic. Visually, I think the Android Market provides a better showcase for apps than Apple's App Store does.