In the KDE 'Control Panel' (can't remember what it's actually called), have a look at the Keyboard Layout applet. If you have multiple keyboard layouts selected, and 'enable keyboard layouts' selected, I believe it puts a little flag icon in the taskbar for you to change layouts.
One obvious way to get rid of it is to have only one active keyboard layout. If you have multiple active layouts but want to get rid of it anyway (can't see why you would, but hey) it may be a little harder. Perhaps unchecking the 'enable xkb options' will help, perhaps not. In any case, the process itself is called kxkb.