Amazon's always worked hard to make sure it's in the digital goods business as well as its obviously successful physical one, but this might be one of its boldest steps yet: another app store for Android. We heard the rumor a couple weeks ago through TechCrunch, and The Wall Street Journal is now claiming to have proof, including an Amazon document explaining some of the terms to the developers. It's apparently still unclear when the store will be launched or even what it'll be called, and since so far it seems like Amazon is mainly talking to developers about this behind closed doors, some of the specifics might still be in the air. According to the WSJ, Amazon stipulates an app can't be sold for less anywhere else (which was hinted at in the earlier leak), and there's a stranger requirement that the app can't be on offer anywhere else for more than two weeks before it's given to Amazon. We're guessing that's an Android only stipulation -- or else a bit of a high barrier for iOS ports -- but that just brings up more to worry about: is Amazon building a store just a first in an onslaught? And is this indeed part of an Android tablet launch for Amazon?