You can 'publish' animations in Flash as gifs, but you'll need to fiddle around a little with the publishing settings if the colors get screwed. Also, the file sometimes comes out blurred, and you don't get a transparent background (but someone from here can probably fix that for you when you're done).
What I usually do is copy/open an existing emoticon like
into MS Paint (or Photoshop, or Paint Shop Pro) and change it frame by frame, copying each frame into a gif animation program. Most animation programs probably also have a function to erase the background color and make it transparent, but I've never worked with Adobe Imageready.