I don't know how to get more than one image in the animation bar, but I can tell you how to make the fading effect.
Open a .psd in ImageReady and go to windows>animation to open the animation bar if it isn't already.
Select you layer, now this is the only thing that'll appear in the animation bar.
Near the bottom of the animation bar there are many clickable things, click on the 'duplicate current frame' box.
On the duplicated frame, lower the opacity as much as you want. Do this many times, making new frames and lowering the opacity each time.
If you wish to change the speed of the fade, there is a small bar beneath each frame that should say 0.00 as default, click on that and a speed menu shows up. Change all the frames to that speed and you're done.
Here are a few examples of the fading effect
http://img505.imageshack.us/img505/8893/fade1te7.gif http://img179.imageshack.us/img179/2...less8v2wn7.gif
I'm going to keep trying to get more than one image into the animation, but there's that if you didn't know already.