Android Market Web Store is the webapp that gives you access to the Android Market from your computer. It's the way to manage applications from the computer.
You have to link your computer and phone using your account and it works like a remote control. What you do in the computer will be done in the phone.
Browse the catalogue, search for the applications you need and discover new applications you may like.
Android Market Web Store is the best way to access Android Market in a big screen.