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

Hi,

I have installed postgresql-serve using yum
hba.conf group and owner were postgres then i changed it to root.

when i type psql -U postgres command ( as root user) I get:

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

My file permission are:
drwx------ 5 postgres postgres 4096 2008-09-06 00:36 base
drwx------ 2 postgres postgres 4096 2008-09-08 21:44 global
drwx------ 2 postgres postgres 4096 2008-09-06 00:36 pg_clog
-rw-r--r-- 1 postgres postgres 3200 2008-09-08 21:35 pg_hba.conf
-rw------- 1 postgres postgres 1460 2008-09-06 00:36 pg_ident.conf
drwx------ 2 postgres postgres 4096 2008-09-08 15:52 pg_log
drwx------ 4 postgres postgres 4096 2008-09-06 00:36 pg_multixact
drwx------ 2 postgres postgres 4096 2008-09-06 00:36 pg_subtrans
drwx------ 2 postgres postgres 4096 2008-09-06 00:36 pg_tblspc
drwx------ 2 postgres postgres 4096 2008-09-06 00:36 pg_twophase
-rw------- 1 postgres postgres 4 2008-09-06 00:36 PG_VERSION
drwx------ 3 postgres postgres 4096 2008-09-06 00:36 pg_xlog
-rw------- 1 postgres postgres 15336 2008-09-06 00:36 postgresql.conf
-rw------- 1 postgres postgres 49 2008-09-08 21:44 postmaster.opts
-rw------- 1 postgres postgres 46 2008-09-08 21:44 postmaster.pid

How could i achieve this..
Regards,
Vikas