First obtain one of the compressed source distributions above.
I will assume that you grabbed the bzip'd file
(cidentd-0.2.1.tar.bz2).

Uncompress it:
    bunzip2 cidentd-0.2.1.tar.bz2
This leaves you with the file "cidentd-0.2.1.tar"

Add the spec file:
    tar -rf cidentd-0.2.1.tar cidentd.spec

You may then use rpmbuild (with one of the -t options)
to create an rpm.  Most likely you will want to
install, so you would do
    rpmbuild -tb cidentd-0.2.1.tar

Consult the rpmbuild manpage for more information.