Are there any plans to integrate Skype (for Linux) with any of the more widely used PIM applications like kontact/kaddressbook or evolution?

As of KDE 3.3, kaddressbook will provide an option to use a script to dial numbers directly by clicking on it. It would be very convenient if I could use something like "skype --dial ..." there to dial numbers.
This command should contact an existing instance of skype or start one and then start dialing and return.

KDE 3.3 is not released yet, and I don't know if the same is possible for evolution, but it could also be used elsewhere. We could add desktop shortcuts or even keyboard shortcuts to call our friends etc.
It would help a lot to integrate Skype into the user's desktop environment with little effort. Or is this even possible already..?

It's not yet possible but it's in our plans. Skype will have better commandline options (currently none) and advanced API hooks for doing all this.

Wow, thanks for the quick reply That's good news.

You say that an API is planned for upcoming versions. Do you already know what that API might be good for?
Is the focus mostly on call control or also contact list management? Or do you even plan to make skype usable as a library without own gui?

No library - Skype must be running in the background. Although main window can be hidden of course.

The functions will be along the lines of making and receiving calls and IM-s, navigating call history, doing searches etc - actually most of the functions you can do in UI. And one principle is that you won't be able to do things related to privacy or user settings - you cannot change privacy settings or delete histories (or the API might call the function, but Skype main GUI warning still pops up).