Evidence of the incoming Amazon App Store has reportedly been sighted in advance of the retailer's official launch. AndroidNews.de found that visiting amazon.com/apps shows a selection of 48 titles already in the retailer's catalog, including Scan2PDF, EasyTether and Space War HD.
None of the titles have a product page as yet - clicking them goes straight back to the Amazon homepage - but they do have pricing information. A quick comparison against the official Android Market, and it seems there will be some variation in prices, though one download store isn't conclusively cheaper than the other.
Note, we had to log out of our Amazon account in order to see the apps; otherwise our personalized Recent History recommendations squeezed out the software suggestions. However, the listings are still visible at time of posting.