CentOS 4.1 is now released for all the current CentOS 4 arches (i386, x86_64, ia64). CentOS 4.1 has now been set to be the default version for CentOS 4.
These changes are currently syncing the the Mirrors and it may take up to 24 hours for some external public mirrors to get synced. The mirrors at http://mirror.centos.org/
should be updated within a couple hours.
When all the syncs are complete, you will be upgraded automatically from version 4.0 to version 4.1 they next time you run:
Thanks to Pasi Pirhonen (blahee on IRC, ia64 maintainer) and Karanbir Singh (z00dax on IRC, helped greatly with i386 and x86_64 arches) for this release.
Johnny Hughes (hughesjr on IRC)
CentOS 4 Lead Developer