WP101 has a library of tutorial videos that are perfect in their simplistic explaination. The first video in this series provides an overview of the WordPress Administration Panel, which provides access to the functions and features of your WordPress-powered website.
Covered in this video:

Familiarizing yourself with the WordPress Dashboard.
How to customize the WordPress interface just for you.
Hide Dashboard modules you rarely use.
The collapsible navigation menu and functions.
The default modules that are available to users.
How to use the Quick Draft module to quickly save ideas.