I want to add a note. Huskermania
's How to Root a Nook Color has you rename the .img file to "root.img" from whatever version of AutoNooter you downloaded. This is so great because when I was getting ready to root I was confused by what to enter in Terminal. This way you don't have to worry about entering the wrong info. You simply enter:
dd if=/Users/YourUsername/Desktop/root.img of=/dev/disk#
I thought that was pretty cool.