Postgres.app is the quickest, easiest way to start working with PostgreSQL on your Mac.

It is strongly advised that you do not use Postgres.app in a production environment. However, for learning about PostgreSQL and using extensions such as PostGIS, Postgres.app makes server installation and set up a snap.

Installing Postgres.app

Download the disk image for the application. Move the Postgres.app application to /Applications and then launch.

You will also want to see how to modify your $PATH to access the included command line tools.