When will athletes for the 2012 Olympics be chosen?

Question

for swimming, gym, relays, cycling, etc.

Answer 1

i wanted to know that to and when are the next olympic trials

Answer 2

At the next Olympic Trials.

Answer 3

When?

They have to meet the minimums of the federations of the sports they practice.

Sports in which the winners are decided by votation have different rules.

I'm not absolutely aware of those, but I know it has to do with their results in the World Championships.