It's hard to totally disprove these first Chrome OS shots, though there are plenty of reasons to be suspect. Setting our scepticism aside for a second, here's what alleged leakster allegedly saw, allegedly:
As an employee of a parts supplier for Acer, one of Google partners for Chrome OS (true!), he was privy to a brief demonstration of a Private Developer Beta. They showed a full installation, which took about 10 minutes. After installation was done, desktop to desktop reboot took about 25 seconds.
As for the desktop, it was minimalist: at the bottom of the screen is the Chrome Bar, which is the system's dock, start menu, or whatever you'd like to call it. The glowing blue icon, which looks like the centre of the Chrome logo (also true!), opens the main menu, and hides when not in use.
Now, some reasons to be suspicious: these shots come a little soon for my comfort, just one day after the announcement; the shots could easily be mocked up in an existing Linux desktop environment (this one looks a bit like XFCE, actually); the shots don't necessarily look like they were taken in an Acer conference room (floral table tiles? really?); and, most damningly, the colours in the word "Google" are ordering incorrectly. Lastly, the demo was carried out on a Acer Extensa 4620Z, not a netbook, which is Google first target.
But you can see the same pictures I can, and description in the leak is quite long, so just have a look for yourself. I'm just not overly hopeful. [ChromeOSLeak—Thanks, Matt!]