hiya,
what you need to do is decompile the flash file that you want to use the icons from,
open this decompiled file in macromedia/adobe flash and export the icons.
if you are just wanting to use different flash manus with your own themes you should download a program called SetFlashMenu, this will allow you to right click on "any" theme file and in the "send to" menu chose setflashmenu and enter the name of the flash file where it says "ChangeMe.swf.