I thought long and hard about answering this. What's "normal language" for "copy this image file to a micro SD card of at least 2G capacity"? Especially when the answer depends on what OS you're running on your PC?
You see, rooting a NC isn't something I'd want to try to explain to somebody who didn't have a good mental model of what's going on inside, even something as well-designed as the NC. I'm a lifelong Unix/FreeBSD/Linux kernel hacker (but new to Android), and it took me several weeks to figure out the terminology (some terms are new, some terms have changed meaning since I learned them), and people are horribly imprecise in what they say.
You might want to start with the Nook Color Portal. They're much less hard-core than the folks doing the cutting-edge work on the NC (xda, cyanogen). It's very easy to get lost in the tech jargon.
Part of the problem is that you have lots of mutually-exclusive choices (rooted stock, NookieFroyo, CM7, HC) (SD, emmc, both), and most of the people who speak up are invested in their choice and think that their choice is right for lots of other people.
Personally, I'm running CM7 off an SD card with the menu u-boot, with stock B&N 2.1 on the emmc. Now that the Nook Android app supports magazines, I just might install CM7 directly on emmc and run that way. When those sentences and those choices make sense, you're not confused anymore!