Recently I was out with a collegue having a drink and the question came up as to the real meaty difference between management and leadership.  Here is my take-- not my own ideas by any means, but highly distilled from a number of thought leaders.
 
Management is defined by 1) Position and 2) Things you Do

Leadership is defined by 1) Influence and 2) Other Things you Do

Because influence is greatly dependent on other people it’s much easier to be a good manager because in theory you have more control.

Because influence is usually derived from the “Things you Do” as a manager, I believe it’s USUALLY true that a good leader will also be a good manager, but not necessarily the other way around.  The exception to this is that rare leader who lacks the POSITION, but still manages to gain influence and does all the right things.

Finally, I think you can boil down the difference to a matter of focus:

Good managers focus on doing things right.

Good leaders focus on doing the right things.