Lost in the shuffle of setting up a database server is the question of getting data in and out of it. Usually, the need for a database comes from an application, but how do developer's get to that database.
What we offer, for the most part just packaged versions of the PostgreSQL packages from the GBorg website, and as such are covered by those licenses. At the moment, the only ones packaged in this are the JDBC driver and our PGSQLKit (as well as our original pgCocoaDB which is slowly being retired). However in the future we will also be packaging the ODBC driver, the npsql library for use with Mono/.NET and of course our own PGSQLKit Framework that all of our Cocoa / Objective C tools are built upon. In addition, we will be making available a developer’s statically built tree that installs to /opt/local for building statically linked binaries. For the moment, this download is part of the unified installer.
There are other alternatives for the Mac as well. There are commercial ODBC drivers that work well. There are also several other projects to provide access on the Mac, please be sure to check them out. There is also a 'sort of related' project, the ODBCKit, also authored by Dru and supported by Druware Software Designs that provides access from Cocoa to PostgreSQL databases via ODBC.