Start off by starting a new movie: File » New. Then go to Modify » Movie and change the width and height to whatever your preference might be. The one I’m making is Width: 550 Height: 400. Then using the text tool, write whatever you want the text to say.
Okay great, next you want to highlight the text, so the blue border is around it, and go Insert » Convert to Symbol. Choose name: “Text” and behavior as a Movie Clip.
Right Click on the text and choose Edit In Place. Now we’re in the movie clip. On the timeline, you should see on the top left, the name of the layer entitled, “Layer 1”. Double click that and rename it “Moving Text”. Now select the text like we did before and Insert » Convert to Symbol again. This time name it “Text Over” and behavior as a graphic.
Now you want to select the text and press Edit » Copy and make a new layer. Name the layer “Static Text”. Add a keyframe on both the layers up to 20. On the Moving Text, right click on the first frame and choose “Create Motion Tween”. On the 20th Frame of the Moving Text, go to the effect tab, select Alpha from the drop down and choose 0% Opacity.
Finally, click the scale button and click the middle right white box on the text, and drag it as far as you want the effect to go. Go to File » Publish and you’re done. Not too hard was it? You can click the image on the left to see a larger picture.