Running on different host

Hello.

How can I connect from Web to PostgreSQL running on
another host? What do I need to set in PostgreSQL
configuration?

I'm using p5-Pg to access in on localhost. Thet's the
initialization part (Perl):

use Pg;
$conn = Pg::connectdb("dbname = somedb user = someuser port=5432");

How do I add host in second line?

   +---------------------------------------------------
   :                                           \  \ .":
 ^.-.^   All-Russia Webmasters Club webmaster   \ ."-.:
'^\+/^`                 http://www.webclub.ru   ."-...:
'/`"'\`                                       ."      :