Note that you can also simply copy/paste into Notebook (and from Notebook into anywhere else) if you prefer to use another mechanism for writing your notes than Blizzard's
wonderful built in editor
I.e., write your notes in your windows/mac text editor of choice, copy the text, alt-tab to WoW, bring up Notebook, and paste it in.
I have a few tweaks to do on Notebook, just not getting a lot of time to work on my addons at moment, and since its still working, its dropped in priority a bit
-- Cirk