Today is a big day for Android. Amazon is all set to launch its very own App Store for Android later today. In preparation for the launch, the App Store went live for a while earlier today and we have been able to notice a couple of features which could make it truly competitive against Google's Android Market.

Update: The Amazon App Store for Android has gone live. Users can access it by clicking here. The Amazon App Store is however available only for users in the USA. The Test Drive feature has also been removed for the time being.

Like the Android Market, Amazon's App Store also has a description of the app with a number of screenshots. Again, like the Android Market, the apps are categorized as Games, Communication, Finance etc. However, it seems like Amazon has been able to outdo Google's Android Market by offering two very interesting features - Test Drive and Free Premium App Of The Day.

Test Drive

Test Drive is a truly remarkable feature in Amazon's App Store. It allows users to test out the app before actually downloading it or buying it right in the browser. The actual app is run in Amazon's servers and on the client side, users can interact with it from the browser using Flash.

Of course, the app will not run as smoothly as it would on a phone, but it does the job of allowing users to take the app for a spin before purchasing it.

Free Premium App of The Day

Another very interesting feature of the Amazon Android App Store is that they are offering one premium app for free everyday. This is a win for both users, because they get the premium apps for free, and Amazon, because it gives users a reason to check out the app store everyday.

The free app for today is Angry Birds Rio.