What is the best way to give users a shared and/or personal phone book?

Now I have a shared phonebook in sharepoint that users can connect to by using outlook.
users, then, can make click to call directly from outlook (http://sourceforge.net/projects/siptapi/)
Siptapi installation is a pain, because I have to manually install and configure every PC…

We have yealink T20 phones, and nobody uses the phone’s internal phonbook. Actually I’m not able to centrally manage the internal phonebook on that phones.

I feel that my solution is not the best…
How do you have configured your phonebooks in your environment?