I hope this is not an outward facing machine . CentOS 6.0 is 3 years out of date and missing 3 YEARS of security updates
you will likley find that downloading random rpm's is the FASTEST way to royally "bleep"-up your system.
when centos 6.1 came out the 6.0 archive moved to the historical archive " The Vault"
NONE of the repos that were on the 6.0 dvd will work
you need to manually edit them to point to the historical archive
THESE ARE 3YEARS OUT OF DATE !!!!
and are not supported and have not been supported !!!
the VERY LAST updates cent6.0 hade
install the gcc development group FROM THIS REPO
and install the kernel and source FROM THERE
this will install gcc and ALL the extra it NEEDS
yum groupinstall "Development Tools"