I am not sure and this particularly depends on your distro and desktop
environment of choice. On the other hand, I believe the clearlooks style
applies to gnome and hacked to Qt3 based applications. Qt4 applications,
most probably have still no bindings for these uniform eye-candy stuff.
However, you can tweak the generic appearance of Qt applications with
the `qtconfig` configuration utility program. Make sure you're using the
right one whether for Qt4 or Qt3.
Select your preferred Appearance/GUI Style between the ones available.
"Plastik" or "Plastique" are the ones you're seeing on the webpages, but
might not be available on your particular case. For Qt3 it helps having
KDE3 installed so that you get the Plastik style plugin available.
rncbc aka Rui Nuno Capela