AOSupport,
This is pretty easy to set up.
You will need to create a new Notification Device Class. I call mine 'Email', nothing fancy.
Under Message Delivery Configuration in the SMTP/VPIM section, check the 'Outgoing SMTP/VPIM' box (you can also check the 'Incoming SMTP/VPIM' box if it makes you happy), fill in your e-mail server in the 'Outgoing SMTP Mail/Proxy Server field'. Then click the 'Security Modes for SMTP Sessions' link, and check 'Unauthenticated' under Authentication Options (assuming your e-mail server will allow this type of session.)
Now in the Mailbox class you must enable 'Remote Text Notification Capability' in the 'Outcalling (Delivery to Telephone or Delivery to Fax)' area.
Lastly, you must enable and configure Remote Text Notification for each mailbox. In the mailbox, scroll down to the 'Remote Text Notification' area, and fill out this section.