I worked quite a bit porting Froyo (Android 2.2) to the Nook Color in it's early days (I'm also cicada on the XDA forums), and helped a bit getting Cyanogenmod running on it. It's an
amazing little tablet.
Someone was working on a full Ubuntu port, but there are serious hurdles there, so I don't expect to see a 'real linux' on it anytime soon.
NC has a pretty powerful DSP chip, which is really a glorified FPGA, what'd be
really cool is if someone could write an android app that takes advantage of this, might get 20-30mhash or so from it
Unfortunately programming for the DSP chip requires proprietary toolkits from TI, and doesn't look like a walk in the park.