[CentOS] yum install x windows?

Sat Apr 1 19:02:48 UTC 2006
Tom Brown <tom.brown at goodtechnology.com>

yum grouplist and yum groupinstall are what you want to use with yum.

yum grouplist tells you the available groups (similar to the groups
available at install)
yum groupinstall installs them. Keep in mind that the shell won't deal
with spaces nicely, so you'll need to quote or escape.

for example ->
yum groupinstall 'X Window System' 'GNOME Desktop Environment' 'Sound
and Video'

This should get you want you want. If you want kde, use grouplist to
figure out the group name, and swap that group for the gnome group

thanks - seems to be OK but after the packages are downloaded i get this

Transaction Summary
Install    196 Package(s)
Update       2 Package(s)
Remove       0 Package(s)
Total download size: 253 M
Is this ok [y/N]: y
Downloading Packages:
warning: rpmts_HdrFromFdno: V3 DSA signature: NOKEY, key ID 6b8d79e6

Public key for lftp-3.4.2-1.2.el4.rf.i386.rpm is not installed

any ideas? I have installed the key at 
http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-4 so any ideas?