http://forums.androidcentral.com/barnes-noble-nook-color/105519-how-download-run-cm7-off-sd-card-easy-follow-no-root.html#anb

You can read most of it, but you have to register to see the links. He's got links to all the little programs and components you need.

You really do need to read his whole guide first, and I'd read the last several pages of comments too, to see what people are saying. I don't think you need to read the whole thread, it's very long.