Just come across the following tool: http://www.codeplex.com/outlookclicktocall very useful :)

Project Description
This is an Internet Explorer add-on that allows for clickable links for Office Communicator contact names from websites to initiate a phone call with the contact.
This also includes scan and detect of one’s Communicator Contact list and Outlook address book, to allow clicking on the contact’s name to start an Instant Messaging session, and/or to allow CTRL+Click to call the contact using Communicator Automation, or optionally Shift+Click to perform a mailto: via one’s mail client.”