Centos Linux operating system can be downloaded from Centos Public Mirrors. Most of the download locations are at US. Current version is 6.3 now. DVD version consist of two files. CentOS-6.3-x86_64-bin-DVD1.iso and CentOS-6.3-x86_64-bin-DVD2.iso.
http://www.centos.org/modules/tinycontent/index.php?id=15
http://www.centos.org/modules/tinycontent/index.php?id=15