This week saw the release of KDE 3.5.3 (bugfixes and carefully chosen new features) and also the openSUSE Build Service, although still in Alpha phase, becoming productive as it now creates and offers the KDE and KDE applications backports among other stuff.
The supplementary/KDE repository does not exist anymore. KDE and applications backports are now splitted into KDE:KDE3 and KDE:Backports projects (there is also a KDE:KDE4 project which atm doesn't offer more than Qt and kdelibs packages) from software.opensuse.org. This allows you to update an application without having to update your KDE as applications are now built against the KDE version from your distribution. Please read the Build Service for Users page how to add the new repositories to your package manager.
Please keep in mind that these KDE packages are, as supplementary/KDE before, experimental, untested and unsupported stuff and hurting your health by keeping you longer in front of the computer. :-)