IMO, Chromium OS is designed to run on bare minimum of resources.
So, it will run in any laptops manufactured these days.
But before you try to install Chrome OS, make sure you really want it. You won't be able to run any windows apps, couldn't play games, as well as, may not able to play High def movies etc. (But, Youtube videos would play just fine).
So, my suggestion is first analyze your requirement and then go ahead.
Best way to try out chromium os is to download flow from hexxeh.com which is made from chromium os. And only use the stable build, usb boot. Download the file (~ 300mb) and use byte copy software ( whose link you would get from hexxeh.com) and byte copy the file in a usb of minimum 2 gb,( it would format the pen drive). boot your laptop from usb and you would be using chromium os in 10 seconds, if you like it, you can install it on your hard disk.
Caution: it's still in beta, can crash and many things might not be working.