What sounds are especially important in developing this piece and where do images foreshadow later events?I am trying to figure out ifI am...

Hmmm.  I assume you are for sure referring to
Lord of the Flies, since that's the group you tagged your question
with; however, after teaching this novel for years, I've never seen much recurring sound
imagery in the novel other than one thing--the blowing of the conch.  So, I guess that's
what I'll spend a little time on for you.

This is a
symbolic novel, and the conch is clearly a symbol of order and organization and even
civilization on the island.  It is found and used on their first day on the island, and
Ralph blows it only when Piggy suggests such a thing can be done.  The first time he
blows on it, "the shell remained silent."  Piggy coaches him a bit, and finally he blows
the conch with some power.

The effect is immediate.  Out of
the brush and trees, across the sand, boys come and gather around Ralph.  Jack, head of
the choirboys, approaches Ralph and asks,

readability="5">

"'Where is the man with the
trumpet?'" 

The sound of the
conch calls the boys to gather, and the sound is clearly the only rallying cry on the
island.

Soon, though, things fall apart.  The conch has
lost its strength as others choose to disregard order and civility.  In chapter 5, one
of their meetings has disintigrated. Piggy tells Ralph to blow it again, but Ralph is
hesitant. 

readability="5">

"'If I blow the conch and they don't come back;
then we've had it.'" 

Piggy
answers,

"'If
you don't blow, we'll soon be animals
anyway.'"

Jack, in chapter 8,
tries to call a meeting, but it is an "inexpertly blown conch" and this meeting marks
the end of any organization on the island.  When the conch shatters, it's over.  So,
what happens to the conch happens to order on the island--it starts strong but fades
to translucency, just like the shell.  There is only
silence.

There are a few other sound imageries throughout
the novel, though they aren't as symbolic as the conch: the sound of fire, the soft
"plop plop" of the parachutist Simon releases, the ululations of the boys at the end of
the novel as they hunt Ralph. 

Hope this
helps!