The script below doesn't remove the database because the second
link is not closed and the postgres will not drop a database if there is a connection using it.

<?php 
        $id1 = pg_connect("host=cheese port=7655 user=zendtest password=******** dbname=template1");
        pg_exec($id1, "CREATE DATABASE zendtest");
        pg_close($id1);

        $id2 = pg_connect("host=cheese port=7655 user=zendtest password=dnez dbname=zendtest");
        pg_close($id2);

        $id3 = pg_connect("host=cheese port=7655 user=zendtest password=******** dbname=template1");
        pg_exec($id3, "DROP DATABASE zendtest");
        pg_close($id3);
?>