If you don't want to re-install your desktop with CentOS-5, you can 
install the pre-built vmware guest at:
http://dev.centos.org/~tru/vmware/centos-5/CentOS-5_desktop.i386.zip
and add needed rpms from the aria.repo

see http://dev.centos.org/~tru/vmware/centos-5/changelog.txt
and http://dev.centos.org/~tru/vmware/readme.txt
for details on the vmware guest machines