You're right, a small system to administer news items IS very simple, but not obviously so to the novice. It's something you should just dedicate a weekend to and get a grip on because you don't want to be turning away work. Once you have that figured out, many other possibilities will open up. Trial and error is your friend.
For something like that you don't even need to bother with a user management system. Just pop the files in a directory called 'news_admin' and password-protect that directory via the host's control panel.
Data-assist will actually auto-create all of the insert/update/delete pages for you, then it is a case of integrating them into your site template.
At this point I should give a few pointers but I need to head out. If I grab some time later I'll aim to help :).