The gateway to subscriber list managemnt tools is the link labeled subscriber list on the admin main page.
Here you can view a list of the subscribers, and visit links from there:
Send an update
This page allows you to send a manual note to the subscriber list. This is useful for notifying particular events like a major overhaul of the webspace.
Modify subscriber list
Here you can if need be delete a particular subscriber. The need for this may arise if a persons email address is bouncing emails for example.