INSTALL

System-wide install:
Extract this archive to $KDE4ROOT/share/apps/desktoptheme directory,
where $KDE4ROOT is the location where your KDE4.0 is installed.

User-only install: (kudos to boardercoach for reminding me of this)
Extract this archive to ~/.kde4/share/apps/desktoptheme directory

HOW TO ACTIVATE

Open your plasmarc file (~/.kde4/share/config/plasmarc) and in the
[Theme] section replace name=Default with name=slim-glow

When you restart plasma, the new theme will be loaded.
(you can log out, and log back in)