Ok this will teach you how to make a fading text animation.
Step 1. Open the Image you want to have the fading text on.
Step 2. Create a text layer with a word, phrase, anything.
Step 3. Press Ctrl+Shift+M to jump to imageready.
Step 4. Now on imageready, create a new frame on the animation window.
(to create a new frame, press the button right next to the trash can on the animation window in the bottom left corner)
Step 5. On frame 2 select the text layer and set opacity to 80%
Step 6. Create a new frame, and set the opacity to 60%.
(Continue doing this until you reach 0%.)
Step 7. Now Create another frame and start going up with the opacity by 20% until you reach 100%.
Step 8. You're done! you can press play and see how it looks!
My final Result with a bit of my sprucing up:
(Note: If you change the opacity by different intervals, then it will look different.)
P.S. Thanks Wolf for some additions to the tut.