I just bought my Nook Color a couple weeks ago. I had 1.4.2 and I'm using a cheap $6 sd card. Use ManualNooter to root it. All the links for this stuff have already been posted in this thread.
On your computer
- Download and open winimage
- disk > restore virtual hard disk image on physical drive
- flash the clockwork img file to the SD
Use the one for your sd size. I had a 4gb card so I used 4gb_clockwork-18.104.22.168 (there is a list of them)
- Once complete drag and drop Manual Nooter 5.02.19 and Apps2SD Stock Kernal onto the sd
Plug the sd car into your nook and turn it on. Once you get to this point you should be able to follow the directions on the regular manual nooter page. Which is something like.
- Wipe all data, cache, ect.
- Install zip from file - ManualNooter #___
- Install Apps2sd file
- Take out sd card, and reboot
Then from there you can install other roms the same way you installed the manualnooter zip, or use rom manager