Step 1
Create a new movie, then type a text.  I recommend using a bold font, size 50 or bigger.

Step 2
Break apart the text object into curves by doing Modify->Curves->Break Apart.   The reason we do this is because a text object cannot be colored with gradient, only curves can.

Step 3
Copy the text object.

Step 4
Create a new layer and paste-in-place the text object onto the new layer.  (To paste-in-place, do Edit->Paste In Place.)

Step 5
Now there should be 2 layers on the movie.  Hide the top layer.

Step 6
Select the text object on the bottom layer, then expand the text.  I'd use about 8 pixels distance.

Step 7
Fill the text with a different color, then un-hide the top layer.  Notice that now, the top layer contains the text and the bottom layer contains the outline of the text.

Step 8
Open the Gradient palette and create a gradient that looks something like below (darkGray-white-darkGray):

Step 9
Now select the text on the top layer and fill it with gradient.  You can be creative here.  For example:

One sweep horizontal.

Multiple sweeps vertical (this requires painting each letter separately).

Single sweep diagonal.

I'd use the last one for now.

Step 10
Change the movie background color to black.

Step 11
Hide the top layer and fill the bottom layer (the outline) with a slightly darker version of the gradient.  Again, there are some variations possible here:

Multiple streaks.

Single streak.

For this example. I'd use the single streak because it looks more uniformed.

Step 12
Un-hide the top layer.  The result should be something like below.

If using multiple streaks on the Step 11, this is what it might look like.

If using single streak on the Step 11, this is what it might look like.

Step 13
On the top layer, make a key frame at frame 40.

Step 14
On the top layer, make another key frame at frame 20.

Step 15
On the top layer, insert shape tween between frame 1 to 20 and 20 to 40.  Make sure it's shape tween, and not motion tween.

Step 16
On the top layer, frame 20, edit the text object by applying the gradient on a slightly different arrangement.   Here are some examples:

Step 17
Check to make sure the tween works fine.  Do this by clicking on frame 10 and 30.  Flash can have problem when tweening multiple shapes like letters.  Below is an example of a failed tween.

If this problem occurs, then try the following:

• clear the key frame at frame 20
  
• go to first frame of the top layer, select and copy the text object
• create the key frame again, but now delete the newly created text object
• go to first frame of the top layer, select and copy the text object
• paste the text object copied from frame 1 to frame 20
• go back and repeat step 16 onward

Step 18
Test the movie, it should produce the effect like shown on the example above.