<p>Is it possible to use EventListener to Listen to a variable and detect when the value of that variable changes? Thanks.</p>

You used to be able to do something similar in AS2 using Object.watch.  I don't see a direct equivalent, but it looks like
mx.binding.utils.ChangeWatcher
will give you similar functionality for any variables that are bindable.
I don't know of a way to do it in AS3 for non-bindable variables, but if the variable you want to watch is bindable (or if you can modify it to be binadable) then ChangeWatcher might give you what you want.