Based on Ender's Game, is it right or wrong to use children soldiers and why?Please use examples from the book. Please and thank you. =)

There are several points of argument for both the
affirmative and the negative sides of this debate.  For simplicities sake, I'll take the
"in favor of" using children side.

In the context of the
novel, it is really the only choice.  The science fiction nature of this novel
necessarily separates it from our world today--and allows us to consider the events in
the novel as realistic for the context in which they are
presented.

Consider first the reasons children are selected
for Battle School.  They are more moldable ("maleable" as Ender is called) and haven't
created any bad habits yet.  They probably also tend to fight and work hard with less
explanation, as adults tend to become more suspicious of authority and jaded by age. 
Also, at this point in the future, the kids who are selected for battle school are
genetically "weeded" (I don't want to say bred) to be
geniuses.

The last point I'd make in favor of it being
okay for children to be soldiers is that they don't
actually fight in the real war.  They are not at risk of dying.  They are merely playing
"games" on the simulator, completely ignorant of the reality of what is going on. 
Again, this was necessary to get them to take the kind of risks that Ender took.  Had he
known actual humans were out there--he would not have taken the
necessary risks to win the war.  An adult might not have been quite
as persuaded by the aspect that this was all a bunch of "games" done in the name of
training.