I'm playing it on an HP 2133 MiniNote with the following specs:
1.2 GHz single-core VIA processor
2 GB RAM
8.9" display, 1280 x 768
It runs fine. I can't really tell if it runs any slower than it should, especially since on the netbook it plays as fast as the demo video does on my desktop. It loads about as fast as any other game, and the mouse and game respond well. I've never had a hangup or freeze even though it seems to max out my CPU. The only possible criticism is the font is a bit small on a netbook screen, but it doesn't really affect playability.
By the way, I'm using Windows 7 and I think most programs (especially CPU-intensive games) run much better than under Vista. I've also tweaked it to minimize background programs and services, eg, turning off unnecessary things like Aero, using Norton's Silent Mode, and getting rid of all the added crapware.
They did a good job of making it available to us netbookers. Give it a try!