PeaZip is developed to be a standalone, almost autocontained application; the only dependency on Linux systems is for libgdk_pixbuf library.
This is an advantage when it's desired to have a portable application, not needing to be installed on target systems (just unpack the application and run peazip executable), or when a library freeze is desired and shared libraries should not be furtherly changed (i.e. on some production system), or when it's desired to have a single application with almost identical look and feel and features in an environment with mixed systems or desktop managers.
One obvious shorthcoming of this approach is scarce system integration on target environments; FreeDesktop standars (http://freedesktop.org/wiki/Standards/menu-spec) however offers powerful and easy to use methods, using .desktop file scripting, for integration of applications in desktop environments following FreeDesktop standard guidelines (notably, Gnome and KDE).

With following instructions you can easily add KDE integration to PeaZip:
1) link peazip binary in one of the system's binary folder i.e. /bin or /sbin or /usr/bin or any path fit for your system;
2a) copy peazip.desktop file in /opt/kde*/share/applications/kde if you want to add PeaZip in KDE start menu (and 'Open with' dialog);
2b) copy peazipdesktopaction.desktop file in /opt/kde*/share/apps/konqueror/servicemenus if you want to add 'Send to PeaZip' action to Konqueror's context menu: single or multiple files (of any type) and folders can be sent to PeaZip which will then determinate the action (open or add to new archive) depending on file type.
* replace /opt/kde* with your system's path for KDE; usually 'kde' is follwed by major release number, like i.e. 'kde3'.