Use Emerald window decoration themes in KDE 4
With the Smaragd windec package: http://dl.dropbox.com/u/1540715/smaragd.zip
(32 and 64 bit deb files)http://kde-look.org/content/show.php/Smaragd+%28Emerald+for+KDE%29?content=125162
in case you have become bored and want to play with the 1500 available themes.....
You can manually extract your chosen theme's .emerald file (it's just a gzipped tarball), then extract the .uncompressed file into your (HOME)/.emerald/theme folder, which will make it the default smaragd theme.
Possibly installing emerald from the Repo of Shane will also handle the switching of themes in the Emerald Theme Manager, but I have not tested this yet.