At long last, my PowerToy is live! Send to OneNote from Outlook lets you send Mail, Post items and Sticky Notes to OneNote (note, this was previously called Outlook2OneNote).
While you are there I also recommend Send to OneNote from Internet Explorer.
Both of these use the OneNoteImporter that Donovan created.
A lot of folks at Microsoft were instrumental in dogfooding the product as well as answering my never ending questions about managed programmability in Office 2003. Special thanks to Siew Moi Khor and Misha Shneerson for showing me the light.
Note, if you install this PowerToy and you do not see the toolbar icons in your Outlook standard toolbar this is because the Outlook 2003 .NET Programmability Support is not enabled. To fix this you must:
Uninstall the PowerToy if you have already installed it
From the Start menu, select Control Panel, and click Add/Remove programs.
Select Microsoft Office Professional Edition 2003, and then select Change.
Select Add or Remove Features and click Next.
Click Chose advanced customization of applications.
Expand Microsoft Office Outlook, and confirm .NET Programmability Support is set to Run from My Computer.
update: seems Peter has found some bugs.
Navigate to Selected Item is broken. It is supposed to take you to the OneNote page you created from the Outlook item
Sometime the message header isn't coming across. Not sure about this one yet.