OOo 2.0 has enhanced PDF export support. Now there are bookmarks as default, and
"notes" are exprted as annotations in PDF.

But notes cannot be edited in Acrobar Reader. As a teacher, I see convenient to
be able to add comments to a document sent to me as an assigment by students
using OOo. The editable OOo format would be less suitable, PDF keeps fidelity in
the main text, while allowing to add notes.

I suggest to add a new option in the PDF options dialog open by "export PDF" to
allow the setting of suitable permissions in the PDF for annotating, printing
etc etc. 

- Enrique -