When Google's Vice President of Engineering Vic Gundotra announced Froyo in his keynote for Google I/O 2010 last May, he showed that they are working on a new website where we will be able to search, browse, and install apps directly from the website. However up to this day (January 2011), no more words has been heard of that website ever since.
Note that everything in this paragraph is speculative: My guess is that they are holding back the website to launch with Honeycomb or probably for Google I/O 2011 (or they may be going to
announce Honeycomb on Google I/O 2011 (EDIT: no, they just given peek preview of Honeycomb's tablet feature at CES 2011, they haven't released any Honeycomb device yet though (EDIT2: Honeycomb is now released)). Also, it is possible that web install will only be for Android 2.2 and above due to C2DM requirement, though Google might have other solutions. Another possibility is they are scraping the site, and are now wishing for everyone to forget what they were saying in front of thousands of audience and practically eternal Youtube audiences. But keep in mind that it's really up to Google's strategic, on how and when they will launch the new site. (EDIT3: Android Web Market have been released for some time now at https://market.android.com/)
For now, though, AppBrain and AndroidZoom provide similar functionalities.