|When you say Outlook Notes ... do you mean OneNote ?|
If that is the case, a password for your notes in a secure Windows environment should suffice. It will allow you flexibility and mobility too. I would do this as well as encrypt a section.
Here is a good link to help explain ... http://office.microsoft.com/en-us/o...
I only I use the password protect and find it very convienent.
The biggest destroyer of your security will be you - keep that in mind!
I'm still learning everyday.