Road Cycling - please explain few things about racing

I've been watching race (Giro, Tour, Vuelta, etc) for quite some time but still don't understand
parts of what's really happening or what the announcer is saying.
Can you explain some of them? I don't race, dont' even ride
that much, thus the lack of understanding.

1) a pursuit group of say, 5, riders, chasing the leader. the
announcer says "but no one is cooperating" Question: what's meant by
cooperating, what would I see happening on TV if they were indeed
cooperating.

2) a rider from a team "leads out" his team-mate (the main rider of
his team) towards the final sprint and drops out to the side when he's
all out of energy. Why do the main rider need to be led out towards
the final sprint?

3) a small group of riders, why is it the front rider is said to be
"doing all the work" is it that difficult to be in front.

4) if for e.g., Heras is taking Armstrong up a climb, is it more
mental help that he is providing or is there some physical advantage
of following somebody.

5) "rider A and his mates decides to drop rider B" how is this drop
accomplished (other than just sprinting away, is there something
else"?

6) if someone is right in the middle of a big peleton and needs to go
somewhere (anywhere for whatever purpose) how do they get out of
there?

I think I will enjoy watching the race even more if I understood some
of these things.
Thank you.

http://www.exploratorium.edu/cycling/aerodynamics2.html

That will answer a few of your questions.

1) what's meant by cooperating? Taking turns pulling, i.e., riding at the head of the small group -- which is more strenuous with or without a headwind --while the other members of the group would get a chance to rest while riding in his draft.

2) Why do the main rider need to be led out towards the final sprint? Again, any time one rider is in front of another rider the lead rider is fighting air resistance whereas the rider(s) behind them get the benefit of their draft (think NASCAR or motor racing).

3) Why is it the front rider is said to be "doing all the work" is it that difficult to be in front? Yes, riding at the front of a group is much more strenuous, particularly at racing speeds, i.e., the faster you go the more air resistance you encounter.

4) Is it more mental help that he is providing or is there some physical advantage of following somebody? Again, these are pro cyclists who are riding at very fast speeds so it is always advantageous to ride in another cyclist's draft.

5) "rider A and his mates decides to drop rider B" how is this drop
accomplished (other than just sprinting away, is there something
else"? That's pretty much it. There are some tactics that can be used, but in general it is "teaming up" on a rider who does not have anyone else to work with to leave them at a disadvantage.

6) if someone is right in the middle of a big peleton and needs to go
somewhere (anywhere for whatever purpose) how do they get out of
there? They raise a hand to signal the riders around and behind them if it's a sudden need to decelerate (flat tire, etc..) or for non-emergencies you just adjust your speed and let the riders around you know where you want to go.

A few more tips:

http://members.shaw.ca/bastionsquarecyclingfestival/spectator-guide.html