Tuples

Tuples is a PostgreSQL database management for Mac OSX.
Tuples supports all major PostgreSQL releases, up to version 9. The same application will allow you to connect to as many servers as you need, providing you with a sandboxed editor for each connection.

The program allows you to export the results of your queries in a number of formats: MS Excel 2004, CSV, Tab Separated Values and HTML so you can share the results of your queries with colleagues or manipulate with specialized tools. Also Tuples displays any errors generated by the database in their original format.
However Tuples has all the features you would expect from a modern database management tool. Syntax highlighting, the ability to open several connections simultaneously, and to have several editors open per connection.