Setting up a CVS server is similar to setting up a local repository (see Creating a repository), but you also have to the following:
pserver 2401/tcp
pserver stream tcp nowait root /usr/bin/cvs cvs -b /usr/local/bin -f --allow-root=root_dir pserver
where root_dir is the path that you want to use for your CVS root directory. By convention, the path should end with CVSRoot, but it isn't enforced.
You can have more than one root directory; just add multiple instances of --allow-root=root_dir.
cvs -d root_dir init
This creates the root_dir directory and populates it with all the things it needs in there.
For more information, see http://www.cvshome.org.