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?
How you get to the database largely depends upon your needs and toolset. At the most basic is the C API found in libpq, as provided by PostgreSQL. From there, the choices are many. For Java applications, the distribution has a JDBC driver. There are several commercial and open source ODBC options as well. But what about a toolkit for the Cocoa developer? There are a couple of options there as well.
We have taken a two pronged approach here. First, we have the PGSQLKit which is a framework for the Cocoa development environment. This is an Objective-C framework written with the intent of being Cocoa like, but also readily approachable by the developer familiar with JDBC, .Net or Microsoft's ADO API's. The second prong is an equivalent framework using ODBC as the underlying communication layer to make bridging to non-PostgreSQL data sources fairly easy. That ODBC layer is the ODBCKit and is also open source from the same folks that put this project together.