CentOS 5 :: Yum Install - No Package VLC Available

I've try to install vlc via Yum command..... but said that there isn't package. What can I do for install vlc (and this is the same thing for Firefox .....)

Here the result:
[root@localhost Bruno]# yum install vlc
Loaded plugins: fastestmirror, priorities
Loading mirror speeds from cached hostfile
* addons: it.centos.contactlab.it
* base: it.centos.contactlab.it
* extras: ftp.plusline.de
* updates: centos.de-mirror-server.de
Setting up Install Process
No package vlc available.
Nothing to do

I've also tru to update Yum ..... same answer ......
[root@localhost Bruno]# yum update
Loaded plugins: fastestmirror, priorities
Loading mirror speeds from cached hostfile
* addons: it.centos.contactlab.it
* base: it.centos.contactlab.it
* extras: ftp.plusline.de
* updates: centos.de-mirror-server.de
Setting up Update Process
No Packages marked for Update