A leak over at Amazon.com (AMZN) has made a bit of its upcoming Android app store available to the Internet, and while it wasn’t working to the point that it could allow purchases, a German Android site was able to get a look at 48 apps the store will offer — and their prices.

Android News stumbled on the Amazon app store over at http://amazon.com/apps. That link now redirects to the Amazon home page, but for a while it would take browsers to the front page of the unreleased app store, where several popular or well-known apps from the Android and Apple (AAPL) iOS spheres were shown.

There are a couple of notable features about the Amazon app store based on the screenshot that Android News snagged before the site disappeared. First off, while the Amazon store shares some overlap with Google’s (GOOG) existing Android Market, there are several places in which Amazon is using its store to undercut the prices Google is offering for the same apps. It’s not exactly a jaw-dropping difference — a point-by-point comparison by Android News shows that Google has a few deals in comparison to Amazon, as well — but it suggests Amazon is working to be competitive against its primary competition in more ways than one.

As Fierce Mobile Content points out, Amazon did the same thing when it rolled out its MP3 store against the dominant presence of iTunes, keeping its prices below Apple’s to help make itself a contender. Expect Amazon to work to keep as many prices below Google’s as it can, whenever possible (it still offers MP3s for $0.99, while iTunes’ songs have popped up to $1.29). So far, though, the prices aren’t anything to cause a mass Android Market exodus.

Amazon is also lining up more exclusive app offers, though. One big addition to the store is a game called Call of Duty: Force Recon, which taps into the first-person shooter game franchise that is literally the biggest property in console gaming right now. The company also has secured a deal with Rovio Mobile, the developer behind Angry Birds, to carry its upcoming film tie-in game Angry Birds Rio exclusively — meaning Google’s Android Market won’t get the game at all. Amazon also gets ads-free versions of Angry Birds and Angry Birds Seasons.

That Amazon is already finding ways to best Google is good news for consumers, bad news for the tech giant. If there’s a legitimate app store competitor out there in the Android space, Amazon is it, and the company is going to be capitalizing on its infrastructure to really push its app store — adding recommendations and links to its traditional retail portals to get customers thinking about apps as the same time.

Competition is good, and Amazon definitely seems to be coming to the fight with its gloves up. Meanwhile, all this activity from Amazon should help Android and Google to quickly become a better platform, increasing the field of apps, pushing Google to improve the Android Market, and evolving the things that the Android platform is capable of doing. Google should be prepared to step up, because if this leak is any indication, Amazon looks ready to rumble — to the benefit of all of us looking for more great apps.