2012 Track and field tryouts?

Question

Hey I am training to be in the 2012 London Olympics for track and field

But the only thing that stands in my way is,i have no clue where the tryouts are and i really need to know

Answer 1

Training to be the US track  teams waterboy?

Answer 2

if you are competing and are good enough to make the team for your country, you will know where the tryouts are before they happen in four years.