Sources
You can find the sources of the latest release on Alioth.
Binary
po4a is a Perl module. It is available as a binary package in many OpenSource distributions (Debian, Ubuntu, Fink, FreeBSD, Gentoo, Fedora, Mandriva, and probably others).
CVS
The latest sources are available from our CVS repository.
It also contains additional modules which are being considered, but are not of a sufficient quality.