libpq++ is one provide very good connector for PostgreSQL
SQLAPI++ is a C++ library for accessing multiple SQL databases (Oracle, SQL Server, DB2, Sybase, Informix, InterBase, SQLBase, MySQL, PostgreSQL and ODBC, SQLite).
Abstract Database Connector is a C/C++ library for making connections to several databases (MySQL, mSQL, PostgreSQL, Interbase, Informix, BDE, ODBC). It runs on Linux, UNIX, BeOS, and Windows, and a dynamic driver loader for ELF OSes is under development
Navicat is Nice GUI tool for PostgrSQL