Drupal for a Community of Practice

One of my clients is wanting to find a platform to build a community of practice for professional development. I am really wanting to get into a comprehensive discussion regarding the use of Drupal as the platform to facilitate the growth of such an educational environment. Could anyone point me toward user groups, websites, drupal resources on this subject. I have found the following title; and believe there should be many good sites discussing this subject.

http://www.jarche.com/2009/01/drupal-for-education-and-e-learning/

Most appreciated. Peter