There's a new Chrome tag page (like the one there now that shows bookmarks) that you can "install" webapps onto your browser. Essentially, it's a shortcut center to the webapps you use. Then, there's the web store.
Clicking the web store icon will give you a web store where you can buy and install webapps. Then it gets added to your tag page for easy access. One example: Plants vs. Zombies.
Really love the idea of this store - though not sure how many people will actually "buy" web applications. The fact that users can only buy apps using Google Chrome, but they'll work in all browsers (IE, Opera and Firefox) could be a big downfall. It needs to be very open to succeed.