Yes, you can set up a Private Area, from the Applications tab in settings.
This creates an entire mini-site that only members can access.
A full mini-site might be a bit overkill depending on what you want to achieve. So an alternative is that you can use the permissions settings to alter the access rights on pages/applications within the main site. e.g., you could set up Discussion Forums, then set the permissions within that app so that only Members can read/contribute to it, or set up some pages in the main site that only Members can read.
In the documentation you'll find information about Permissions.
Joe - Voice Admin