PostgreSQL is the default database on Mac OS X Server as of version 10.7. The standard version of Mac OS X includes only the PostgreSQL commandline client utilities.
Mac OS X Server 10.7 ships with PostgreSQL 9.0. Minor updates are provided by Apple, but not necessarily right after a new PostgreSQL minor release.
There are several other installers available for PostgreSQL on Mac OS X, which is the recommended way to install.
Download the installer certified by EnterpriseDB for all supported PostgreSQL versions.
This installer includes the PostgreSQL server, pgAdmin; a graphical tool for managing and developing your databases, and StackBuilder; a package manager that can be used to download and install additional PostgreSQL tools and drivers. Stackbuilder includes management, integration, migration, replication, geospatial, connectors and other tools.
This installer can run in graphical, command line, or silent install modes.
The installer is designed to be a straightforward, fast way to get up and running with PostgreSQL on OS X.
Advanced users can also download a zip archive of the binaries, without the installer. This download is intended for users who wish to include PostgreSQL as part of another application installer.
Download the Mac OS X installer from BigSQL for all supported versions.
This distribution includes the PostgreSQL server, a graphical component manager, command line and graphical tools for managing databases, plus many open source community components. Integrated components include web and desktop developer tools, geospatial, provisioning & management, compatibility & migration, backup/restore, and integration with external databases (Cassandra, Oracle, SQL Server, Hadoop), and procedural languages (Python, Perl, Java, and TCL).
Postgres.app is a simple, native Mac OS X app that runs in the menubar without the need of an installer. Open the app, and you have a PostgreSQL server ready and awaiting new connections. Close the app, and the server shuts down.
PostgreSQL packages are available for Mac OS X from the Fink Project. Please see the Fink documentation for information on how to install packages.
A list of PostgreSQL packages can be found using the package search tool on the Fink website.
PostgreSQL packages are also available for Mac OS X from the MacPorts Project. Please see the MacPorts documentation for information on how to install ports.
A list of PostgreSQL packages can be found using the portfiles search tool on the MacPorts website.
PostgreSQL can also be installed on Mac OS X using Homebrew. Please see the Homewbrew documentation for information on how to install packages.
A list of PostgreSQL packages can be found using the Braumeister search tool.