how to configure postgresql to display messages in italian

Hello,

I would like to ask you how to configure Pg to display messages in
italian instead of english.
I'm using PostgreSQL versione 8.1.8

For example, my pg display data as:


\d cani
                                           Table "public.cani"
          Column          |            Type
|                      Modifiers
--------------------------+-----------------------------+------------------------------------------------------
 matricola              | character varying(17)       | not null
 iscrizione             | date                        | not null
 nome_cane              | character varying(12)       |


I would like to have it as:
                                          Tabella "public.cani"
        Colonna         |            Tipo
|                    Modificatori
------------------------+-----------------------------+----------------------------------------------------
 matricola              | character varying(17)       | not null
 iscrizione             | date                        | not null
 nome_cane              | character varying(12)       |

thank you,
jo