[h=What is Rooting/Jailbreaking]2[/h]
Rooting (sometimes called jailbreaking) is the process by which you take complete control of the software running on a particular device. Depending on how much effort the device manufacturer put into locking down the device, rooting can be very easy or very hard. Lucky for us, Google made it extremely easy to root the Cr-48. The process is simple but be warned that it involves resetting your Cr-48 to Factory Defaults. Fortunately, the Cr-48 stores very little locally, the main thing you stand to loose is that horrible picture you took of yourself when you first setup the device. The rooting process is:

[h=How To]2[/h]

1. Hold down the power button to turn off your Cr-48 (enjoy the cool logoff animation)
2. Unplug the power cord, and any other devices you might have connected. Flip the Cr-48 upside down.
3. Pop out the Cr-48's battery by sliding the battery lock over.
4. Just to the right of the battery's gold contacts, you'll notice a piece of black tape. Take the tape off. This picture might help you locate the tape.
5. You'll find a simple white switch under the tape. By default, the switch is away from the gold battery connectors. This is user mode. Use a pen, paperclip, or finger of an infant to push the switch towards the gold connectors. Congrats, you're now in developer mode.
6. Replace the battery and boot your Cr-48 again. You'll get a scary message but don't panic, just press CTRL+D on the keyboard.
7. As a security measure, the device will wipe your stateful partition, getting rid of that lousy picture you took on first setup. The process takes 5-10 minutes so while you wait, go clean yourself up in the bathroom for the new picture (sheesh!)
8. Once wiped, the Cr-48 will reboot, Hit CTRL+D to boot again or wait the 30 seconds (just don't press spacebar)
9. Redo the setup process. If you already activated Verizon it should remain activated.
10. Once you're at the Chrome browser, press CTRL+ALT+T on your keyboard to get to the limited crosh shell. This shell was actually available to you before you switched to Developer mode but now if you type "help" you'll see one extra, very useful command. Type "shell" to drop to a full bash shell. You'll be the special user named chronos.
11. Type "sudo su -". Feel the power of root!

[h=Source]2[/h]
Rooting (jailbreaking) your new Google Chrome OS based Cr-48

So, guess I can install Ubuntu 10.10 Netbook with usb. Google family use Linux only. Love the cr48.