Amazon has officially launched its own application store for the Android mobile operating system. Its store interface, which is available today, allows users to purchase third-party programs with through their Amazon account. We tested it on a Gingerbread-powered Android handset and a hacked Nook Color.

Although it's likely that we will see the Amazon Appstore shipped on hardware in the future, it's currently being distributed as a stand-alone market application for end users to install themselves. You have to download the Appstore apk from Amazon and manually sideload it onto your device. You can fill out a simple form to have them e-mail or SMS the link to your phone, and there is also a convenient QR code on the Amazon website.

Although the average Android enthusiast will have no difficulty sideloading the Amazon Appstore, it's not going to be an easy process for regular end users. I barely had to give it any thought when I installed it on my N1, but I doubt my father would be able to do it by himself on his Android phone. Amazon provides relatively clear instructions... with eight individual steps that aren't going to look exactly the same on every phone. If your installation process exceeds four steps, you might as will list a neckbeard as one of the system requirements.

Another point worth mentioning is that some handset makers and mobile carriers-—particularly AT&T-—like to block sideloading altogether. These kinds of issues create a barrier to entry that will limit the number of users who are willing or able to install the Amazon Appstore on an existing Android device. Amazon is making an effort to address carrier restrictions on a case-by-case basis; AT&T says that it is working with Amazon and will provide a mechanism to allow the company's application store to run on its devices.

Once you get the Appstore installed, the setup process is relatively painless—it just asks you for your Amazon login credentials the first time that it runs. The user interface is simple but intuitive. It's generally faster and more responsive than the Android Market application, but we encountered several periods of severe network latency during our tests, during which search was sluggish and applications repeatedly failed to download. It seems like Amazon is still working out some of the kinks in the system.

When you buy paid applications from the Amazon Appstore, it will bill your Amazon account. This aspect is going to appeal to a lot of users. I imagine that there are a lot more people out there who have their credit card configured in Amazon than do in Google Checkout. As always, Amazon does a nice job of making the purchase process as frictionless as possible.

There are also a few things that Amazon does better than Google. The search feature in Amazon's store is actually useful when it loads (Google apparently hasn't brought its pigeon-ranking innovations over to the Android Market yet) and it uses Amazon's nifty product recommendation algorithms to suggest applications that it thinks a user might like.

All of this is great, but there is a key area where the Appstore falls flat on its face: platform integration. It can't tell which applications you have already installed on our device from the Android Market, and it can't perform application installations in the background. In fairness to Amazon, these weaknesses are probably attributable to security restrictions in the platform itself, but it's still tremendously frustrating.

Instead of putting an installation progress bar in the notification panel, it shows a full-screen window with a progress bar during the installation process. It's kind of intrusive and it makes it hard to install a bunch of stuff in parallel.

I think that the Appstore user experience could potentially be made much better on a device where Android has been customized to integrate it as the default application store. For regular end users who have a conventional Android device, the Appstore is a bit of a pain.

Despite the issues, I still found it to be worth the effort. Amazon has come up with some good ways to entice people to install it and open it on a regular basis. Angry Birds Rio, a new movie-inspired version of the popular game, is available for free from the Appstore. Amazon is also making one commercial application available for free every day. Today's free app is the popular Doodle Jump game.

As we will discuss in a follow-up article, the real significance of the Amazon Appstore is its potential for disrupting Google's control over the Android ecosystem. Google currently uses the Android Market licensing terms as leverage to constrain differentiation and insulate the platform from fragmentation. If Amazon makes the Appstore available to hardware vendors under suitably permissive terms, it could radically shift the balance of power away from Google and give the manufacturers and carriers more autonomy.