I have built a set of preview U4 beta rpms for CentOS i386 - these will become the basis of CentOS 3.4 when Rhel 3 U4 is released.
I will not be pushing these out to the mirrors, but they are available at http://beta.caosity.org/centos/3.3/U4beta
The beta packages are not signed.
To add then to yum.conf add :-
name=CentOS-$releasever - U4beta
Please do not use these on production servers as consequences cannot be predicted ..
I'll be rolling some beta isos in the next few days
Any problems - bugzilla ...