The following errata for CentOS-2 have been built and uploaded to the centos mirror:

RHSA-2008:0288-01 Critical: samba security update

Files available:
samba-2.2.12-1.21as.9.3.i386.rpm
samba-client-2.2.12-1.21as.9.3.i386.rpm
samba-common-2.2.12-1.21as.9.3.i386.rpm
samba-swat-2.2.12-1.21as.9.3.i386.rpm

More details are available from the RedHat web site at
https://rhn.redhat.com/errata/rh21as-errata.html

The easy way to make sure you are up to date with all the latest patches is to run:
# yum update