This is the current source package: cups-pdf_2.6.1.tar.gz and its md5-checksum file.
Martin-Éric Racine maintains a Debian package of CUPS-PDF which is part of the official distribution.
For openSUSE packages are maintained at their Build Service.
Remi Collet maintains RPM packages for Fedora, RHEL, and CentOS which are available from the official Fedora and EPEL repositories.
On codepoetry a package for Mac OS X is available. Futhermore, MacPorts offers a portfile.
A build of CUPS-PDF for Slackware can be found on SlackBuilds.org.
Simon Olofsson maintains a port of the current CUPS-PDF for FreeBSD on FreshPorts.
CUPS-PDF is also available in the packages and ports collection of OpenBSD.
A package of CUPS-PDF for the T2 System Development Environment can be found here.