Outlook 2007 and 2010 offer a sticky note option to create notes that can be attached to your email message and then be emailed to a recipient.

Outlook email client allows a user to attach a Sticky Note to the email & send it to the recipient. Learn how to add a Sticky Note to Outlook ...

If you are using Outlook.com, you can add Notes and create Tasks from the web interface. All these additional items get saved in your mailbox so that you can access them from anywhere.