KDocker is useful for example to embed applications like Konsole or Konqueror in the system tray, especially if you keep those opened all the time and need fast access to them without filling up the taskbar space. Debian Lenny does not include it in the official repositories, so you'll have to compile from source and install it manually, but it's included in Ubuntu's repositories, and to install it only do a:
sudo apt-get install kdocker
Available configuration options in KDocker
You can make kdocker start up a certain application and put it in the system tray after the desktop environment is loaded, for example in KDE you can create an executable file in ~/.kde/Autostart/, say konsole.sh, with the following two lines, to automatically start Konsole and embed it into the system tray after KDE is loaded:
Make sure you make the konsole.sh file executable (e.g. chmod 755 ~/.kde/Autostart/konsole.sh).
Or, you can automatically run a CLI application, like Irssi for example:
kdocker konsole -e irssi
Another, more simple way would be to start the application you want embedded, then start KDocker and directly select the window of the application. It also includes an option to 'skip the taskbar', so when the application gets the focus, the window won't appear iconised in the taskbar.
Updated: Sep 13, 2008