It’s become a common trope to say that Facebook and Google are vying to become the operating system of the Internet. But there are some very clear hints of that in Facebook’s upcoming new design, which it just opened up to today in a developer sandbox. (You can see it at http://www.new.facebook.com, although you’ll need to download some libraries to start testing apps with it).

It appears that Facebook is moving closer to becoming a Webtop application, fusing elements of the desktop into the Web experience.

Eagle-eyed TechCrunch reader Ryan Merket (above) noticed something vaguely familiar about the new design. See the menu bar above his profile? Look closely. Its got some handy menus on the left that take him to his profile, his friends, applications, and inbox.

And on the right of the menu bar is a search box. That is the same visual metaphor you find in the menu bar on desktop operating systems.

The menu choices are different than on you desktop, because these tap into Web applications and resources. But the navigation is the same.

Menus on the le