first of all.
Setup the HTTP repository with something like the following setup ..
mount -o loop /home/namran/iso/CentOS-5.4-i386-bin-DVD.iso /var/www/html/centos service httpd start
then boot of each machine with a DVD/ boot CD.
Get upto to boot menu and type
if succeed.. it shall shows the release notes.. screen as follow..
tail -f /var/log/httpd/access.log
then.. just proceed as if for normal installation..
and move to the next machine.. repeat the same.
p/s : this can also be automated with the kickstart..
but have to make sure the hardisk structure is the same for the whole set of PCs..
which could be tricky if wanted to maintain the existing partition structure..
and risk is losing the whole data on those machine.. 🙂
so better off.. go to each machine.. configure the partition table.
verify it manually .. then only give a go !