Members Only Area on WP

I have a client who would like to have a members only area of her blog so that only registered users can access the information. Is it possible to do — where users who aren’t registed or haven’t logged in see something different than people who have registered and logged in? I was reading this thread http://wordpress.org/support/topic/39901 and it looked like it was going in the direction that I was looking for and then suddenly ended.

Thanks in advance!

Heather