The K Desktop Environment

14.20. How do I check which version of KDE I'm using?

Fire up your KDE Control Center. If there's no mention of KDE's version number, then it must be 1.0.

Another clear difference is the 'K' on the panel. In 1.0 it's a black-and-white 3D K, while in 1.1 it's a white K on top of a wheel.

Or if you have installed KDE from RPMs try:
 $ rpm -qa  | grep kde
 kdesupport-1.1pre2-2rh5x
 kdeadmin-1.1pre2-1rh5x
 kdelibs-1.1pre2-1rh5x
 kdegraphics-1.1pre2-1rh5x
 kdemultimedia-1.1pre2-1rh5x
 kdetoys-1.1pre2-1rh5x
 kdegames-1.1pre2-1rh5x
 kdeutils-1.1pre2-1rh5x
 kdebase-1.1pre2-1rh5x
so my current version is 1.1pre2.