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