[gajanan]

You can't purchase anything yet but you can sure as hell browse around. The trick: search for a known application or publisher like AOL. Then backup to "App Store" in the navigation menu. We've got AIM messenger, Twitteriffic, and the Apple Remote control application all for free and an endless supply of games including Super Monkey Ball and more. See anything you like?

Source : Apple App Store now live! - Engadget