This will produce a list of all the kde-related rpm's present on your system.
Then go to the kde ftp server
and download all the packages you have to upgrade - don't forget to also download the corresponding arts and qt3 packages.
Dump them all in an empty directory.
cd to that dir and issue
This will update KDE to the version you downloaded.
I've heard people say that it was best to first log out of KDE into gnome before updating but this is how I did it before and I haven't had any problems.