1. Install NFS
2. edit your /etc/exports file
3. add /pub/rhelX.Y *(ro) (Replace X. Y with whatever number of distro)
4. save /etc/exports
5. exportfs -a
6. mkdir /pub/rhelX.Y
7. mount dvd of RHEL
8. cp /media/dvd/*.* /pub/rhelX.Y
Now run the system-config-kickstart which should walk you through setting up the kickstart file.
The above instructions could be used for the ftp you just need to point people to it. I just prefer NFS over FTP. Also if you use NFS / FTP / HTTP and can't connect, check your firewall and selinux. You may also need to setup some other things like nfs so that it will use specific ports. if you need help I wrote up a post about it not to long ago. see here.
http://www.samuraitux.com/34/iptable...-allowing-nfs/