This leadership vs. management keynote by Marcus Buckingham establishes the utter difference between both. In fact, he believes they almost do the exact opposite.
Marcus' leadership vs. management keynote describes a manager as someone who focuses on making people more productive and achieve greater performance. As for a leader, he describes them as someone who creates enthusiasm and spirit.
The reason these two categories are said to be the opposite is because a manager focuses on uniqueness in an individual where as a leader finds something universal in everyone. In other words, a manager capitalizes on someone's unique skill and exploits it, while a leader takes the common fear of the future and gets people excited about it.