The KDE Simple Programming tutorial teaches how to develop a KDE application. With the only requirement of a little C++ knowledge, and using the latest KDE snapshots, the reader will learn how to build his/her first KDE application from a simple "Hello world" button to a Web browser with a DCOP interface that communicates with a bookmark application running in a separate process. There's also a spanish version of the documentation.
kdf gives you a graphical overview of your systems disks mounts/unmounts devices by clicking on the devicename, features configurable mountcommands for each device, opens a filemanager to your mountpoint by clicking on it and also includes KwikDisk, which docks into the kpanel and gives you quick access to all devices.
The keeper library provides a simple-to-use C interface for reading and writing configuration data. The data is stored in text files in a hierarchical system. The concept is not dissimilar to that of the Windows registry, but the interface is much cleaner. The library comes with both a command line program and a GUI program for examining and modifying the keeper database.