So, in the wake of the rampant success of the iPad, you can count on Android tablets flooding the market soon. Personally, I can't wait to get one. So far, Android as an OS isn't really optimized for a tablet environment, but the next major revision is supposed to fix this.
Apparently, the Nook Color (which runs a modified, crippled Android under the covers) has been rooted. So as long as B&N doesn't clamp down on this, A nice 7" Android tablet can be had for $249.