The PostgreSQL main website has a new page: "Related Projects".
This page lists the projects which help running and maintaining the PostgreSQL project, the infrastructure, and other things like the translations for press releases. For each project it lists links to the source, as well as information where to send updates, patches, or input.
If you want to get involved in one of the projects, that's your starting point. If a project is missing, please send a note or a patch to pgsql-www.
Many thanks to Jonathan S. Katz for polishing the patch, and making it look nice!