Installing CVS from sources is easy. First, grab the cvs-1.11.tar.gz tarball from ftp://ftp.cvshome.org/pub/cvs-1.11/cvs-1.11.tar.gz (if there's a newer version listed here, you might as well grab the new one instead.) Then perform the following steps (command output has been omitted for brevity):

# tar xzvf cvs-1.11.tar.gz
# cd cvs-1.11
# ./configure
# make
# make install

Now you should be ready to go.