KCall is the telephony application of Kontact.
KCall does this by using KDE's addressbook, which in turn can be a server-based groupware addressbook.
What's New in This Release:
KCall is using the KDE 4 environment now. As part of the porting effort we switched our buildsystem over to CMake. Download the sources and run the following commands:
mkdir build; cd build
You can then start kcall.