Here are a couple of tutorials that shows developers how to use KParts components in a KDE application. In Creating Kparts componets Part 1 you will get an intro to the core KParts concepts of read-only and read-write parts and network transparency. You'll learn how to create a read-only component, and then modify it to be a read-write component. You'll also learn how to deploy the component so that Konqueror can use it.
In Part 2 you will learn how to use the KDE Trader to locate the appropriate component, how to handle user interface merging, and how to embed multiple parts in the same window with the help of the Part Manager.