There are several open sources as well as Paid tools are available as front-end to PostgreSQL. Here are a few of them which are widely used :
It is a command line tool and the primary tool to manage PostgreSQL. pgAdmin
It is a free and open source graphical user interface administration tool for PostgreSQL.
It is a web-based administration tool for PostgreSQL written in PHP. It is based on phpMyAdmin tool to manage MySQL.OpenOffice.org Base
It can be used as a front end tool to PostgreSQL.
It is a log analyzer which creates reports from PostgreSQL log files. Proprietary tools
Lightning Admin for PostgreSQL, Borland Kylix, DBOne, DBTools Manager PgManager, Rekall, Data Architect, SyBase Power Designer, Microsoft Access, eRWin, DeZign for Databases, PGExplorer, Case Studio 2, pgEdit, RazorSQL, MicroOLAP Database Designer, Aqua Data Studio, Tuples, EMS Database Management Tools for PostgreSQL, Navicat, SQL Maestro Group products for PostgreSQL, Datanamic DataDiff for PostgreSQL, Datanamic SchemaDiff for PostgreSQL, DB MultiRun PostgreSQL Edition, SQLPro, SQL Image Viewer, SQL Data Sets etc.