Websites:

Greenleaf Center: http://www.greenleaf.org/
Servant Leadership Blog: www.Servantleadershipblog.com
The Hayes Group International: http://www.thehayesgroupintl.com
SRG (Self Renewal Group), http://www.leadersdirect.com/srgservices.html
Ann McGee-Cooper and Associates: http://www.amca.com

Books:

Servant Leader, Ken Blanchard
The Servant: A Simple Story About the True Essence of Leadership, James Hunter
The Servant Leader: How to Build a Creative Team, Develop Great Morale and Improve Bottom-Line Performance, James Autry
Upside Down: The Paradox of Servant leadership, Stacy Rinehart
Dig Your Well Before You’re Thirsty, Harvey MacKay
Cracking the Code, Dean Lindsay
The Frog and the Prince, Darcy Rezac
Spin Selling, Neil Rackham