CS3 multiple files preloader

Hi All
this is my first post in the kirupa forum.
i just started to learn as3 with flash cs4. i have couple of doubts.

  1. how to create a preloader which need to show by loading a bunch of jpg,mp3,xml and swf files one bye one. the problem face is to get the file size to find the totalbytes before loading a file.
  2. how stop loading of a file while loading in progress.

regards