NookDevs have just posted instructions on how to root the NookColor. This is a big step; when they're ready to share the instructions it means they think it's safe enough for the average user Of course, it's not their fault if this breaks your NookColor, and as always, attempting this process will void your warranty.
On second thought, maybe it's not ready. I'm looking over the steps involved, and I'm not really sure that you should try it yet. It seems to me like it requires a fairly high skill level.