Use pgaccess. It's very nice and clean. It's part of the PostgreSQL distribution, but you must have Tcl/Tk installed and run Postgres with the "-i" flag.
This will cause PG to listen at TCP/IP port 5432 which means you should add an ipchains entry to only allow connections from localhost or some oteh security measure (PG has this in pg_hba.conf if I am not mistaken).