Forgot about COPY command in my previous reply:
$conn = pg_pconnect("dbname=foo");
$fd = fopen('file.dat', 'r');
pg_query($conn, "copy bar from stdin");
while (!feof($fd)) {
pg_put_line($conn, fgets($fd));
}
fclose($fd);
pg_put_line($conn, "\\.\n");
pg_end_copy($conn);