[CentOS] CentOS 5 Beta - Yum Updates?

I am new to CentOS.  I mostly use
Fedora Core.  I installed the CentOS 5 Beta
on a test machine from the DVD.  I configured
it with both KDE and Gnome.  I am using
the default YUM configurtion which loaded
with the DVD.

Unlike FC7T2, CentOS 5 Beta does not seem to pick
up Yum updates.  Is this by design or do I
need to add repos to my /etc/yum.repos.d?

Thanks for any suggestions

Bob Styma