You can share your notebooks for sure.
In your Evernote Web account, you will see a new, blue Sharing section in the navigation panel. Click on “sharing setup” to begin the process of sharing your notebooks. Select the notebook you wish to share, then decide whether to share that notebook with individuals or the world.
There are two additional options under the “Share with individuals” category:
- Share with individuals (view only)
- Share with individuals (view and modify) – Evernote Premium feature
For added security, you can require log in, which means that the unique link in the email your invitees receive can only be used by a single person and they’ll be asked to log in before seeing your notes.
From here: http://blog.evernote.com/2009/06/25/notebook-sharing-phase-1/
Now, if you want to share just a note, you could make a notebook just for this purpose.