Bring clean transparent gif(s) into FlashMX

hi,
how is everybody doing? I am using PNG 24 as my primary image format for my flash animations but the image file sizes are pretty big. I wanna use Gif but whenever I import them into Flash they begin to have halos and unclean transparent background. How can I have a clean transparent background for gif’s if I am using PS’s Save for Web feature…thanks guys!
love,
omar