Re: What is the secret to great agility?
I suppose having powerful and flexible leg muscles for jumping. I remember seeing some basketball players training with these things that looked like giant rubber bands strapping them to the floor and them using those bands as resistance against jumping.
Also, watch the special features on The 300. They show Gerard Butler doing an exercise that seems like it would benefit you.
And of course, there's always plyometrics.
Pilates will increase your agility too.