problem with Postgresql

[creator]

Hi...
i am running runnin psql 7.3.2 (postgresql)under Red Hat 9...i can start the server successfully, but the problem is that i am not able to login..not even as the default 'postgres'..this the error it gives me..:

# psql -U postgres

psql: FATAL:  IDENT authentication failed for user "postgres"

it fails to identify any user. What do i do?
is there a problem with the installation?
or do have to login with some other option? or am i doiing somethin wrong?
Please let me know..Thank you.