As you can see, a list of featured/best selling games populates the front page, along with a list of categories, a "Sign in" button (
which, at the time of this writing, leads to an 'invalid request error'), and a "Search" function. Once you click on one of the apps, you are taken to a page somewhat like the one in the second screenshot, with a description, links to "Overview," "User Reviews," "What's New," and "Permissions" on top, as well as a list of related apps on the left side and a QR code and a "Tweet" button on the right side. Searching for an app brings you to a page similar to the one in the third screenie - nothing too amazing, but functional and easy to navigate nonetheless.
We'll keep you updated as we get more on the Android Market Web Store - in the meantime, enjoy youtube.com/android - I hear something exciting is going down there.