KDE Internationalization site host a pleiade of documents which are very useful for documentation writers, translators and people involved with internationalization. Below is the list:
The KDE Documentation Primer by The KDE Documentation Team
This document tells you everything you need to know to start writing documentation for KDE.
The KDE English Documentation Team exists to provide end-user documentation for the whole of KDE. It's a big task, but an important one. Although KDE aims to be easy to use, not everything is obvious without some help, and, in a project this big, even an experienced user can't know every corner of KDE.
The easiest way to contact the team is the kde-doc-english mailinglist.