Got the kde3 repositories added and the necessary stuff installed.
Can’t seem to get a way into the kde3 desktop as an option in kdm.
Any clue how to get this as an option? I want both kde4 and kde3 as options.
You need to log out of KDE4, select Session>KDE3 and log in again. You can use KDE3 programs that have not been ported to KDE4 in KDE4 but you need to log out and in again to change desktop.
Just to add. You will be needing auto login disabled and then you can choose the session from (lower left corner) of login screen.
Tried that, KDE being the only “KDE” option, no 3 or 4. It always loads KDE4 
Even tried KDE3’s kdm to no avail.
(For one of my older comps that can handle KDE3 fine but gets bogged down with KDE4 even with most of the graphical extras turned off.)
Have a look in your /usr/share/xsessions.
Replace KDM4 with KDM3 as the display manager (make sure it is installed). That is what I did.