problems when i try to connect to my Databasse

Hi........

Firts, sorry with my English. I am from Galician Country.

My problem is :
 i have only one user( in my postgresql)  known as posgres.
# su postgres
#passwd *****

once , i am user postgres , i write : #psql mybd  and it does not ask me for
the BD'pasword ( postgres is like a user root)
The problem comes when i am  running a script php , where I try to connect to
my BD-----> $db=pg_connect("user=$user dbname=$dbname "). This refuse the
connection because  I dont have the password.!!!!!.

How can i get it??????????????????????



Thanks...................

 NUNCA MAIS!!!! , GOVERNO DIMISSOM!!!!!        FORÇA GALIZA!!