The following errata for CentOS-2 have been built and uploaded to the centos mirror:
RHSA-2009:0020-01 Moderate: bind security update
Files available: bind-9.2.1-11.el2.i386.rpm bind-devel-9.2.1-11.el2.i386.rpm bind-utils-9.2.1-11.el2.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