David our storage PM for OneNote just blogged about storing OneNote sections in Groove, here is how he starts off:

Many people have wondered how OneNote 2007 and Groove work together (or not). Your experience will depend on whether you're using a Groove Workspace or a Groove Folder Share. Here's a brief summary...

Read the rest here: OneNote 2007 and Groove. Thanks David! I have been bothering him about this for the past couple weeks : )