OneNote also makes organizing notes by subject and date a hell of a lot easier. I'm gonna miss it when my macbook comes.
Did some searching, and it looks like there are a few mac-friendly programs that try to do the job:http://forums.macrumors.com/showthread.php?t=426460
I've tried most of these and here is my take:
Notebook mode in Word- probably the best bet, but is lacking some crucial features.
OmniOutliner- hated it.
CircusPonies notebook- 2nd best of the bunch, but didn't like that I had to use the mouse to do a lot of things instead of just a combination of enter/tab/etc. like word. They offer a free trial which I did but in the end I was unhappy with how it divided pages on the screen and when printing to PDF and that is important to me.
Evernote- good in theory but had way too many features for what I need it for.