PostgreSQL is already being used by many different application packages, so you may find it already installed on your servers. Many Linux distributions include PostgreSQL as part of the basic installation, or include it with the installation disk.
One thing to be wary of is that the included version of PostgreSQL may not be the latest release. It would typically be the latest major release that was available when that operating system release was published. There is usually no good reason to stick to that level—there is no increased stability implied there—and later production versions are just as well supported by the various Linux distributions as the earlier versions.
If you don't have a copy yet, or you don't have the latest version, you can download the source code or binary packages for a wide variety of operating systems from http://www.postgresql.org/download/.
Installation details vary significantly from platform to platform, and there aren't any special tricks or recipes to mention. Just follow the installation guide, and away you go! We've consciously avoided describing the installation processes here to make sure we don't garble or override the information published to assist you.
If you would like to receive email updates of the latest news, then you can subscribe to the PostgreSQL announce mailing list, which contains updates from all the vendors that support PostgreSQL. You'll get a few emails each month about new releases of core PostgreSQL, related software, conferences, and user group information. It's worth keeping in touch with these developments.