BuddyPress.org

Toni,
You won’t be able to offer your users blogs until BP 3.0 is released. Or you’d have to change your standard WP install to a WPMU install, but it will be much easier to just wait for BP 3.0. Once BP 3.0 comes out there will be an option where you can change a standard WP install into a Multi Blog one where your users can start blogging.