Start up Flash and create a new document. My example above is 300px wide by 200px high. Next create a new graphic symbol, (Ctrl-F8), call it 'content'. Into this graphic symbol you add all the graphics you want to be able to scroll to, in their correct sequence, side by side. For this example, I just made a rectangle using the rectangle too and filled it with that awful rainbow gradient that comes standard with Flash. I then put, at regular intervals, the numbers 1 through 5 using the text tool. Thus, my example has 5 content sections, but you can adapt this to encompass as many as you like. For this effect to look decent you need content that blends (WebAgent does this particularly well).

OK, assuming you've done that right you should have one continuous looking graphic symbol called 'content'. Now create a new Movie Clip symbol (Ctrl-F8) and name it 'bar'. In bar you want to create four layers. From top to bottom label the layers: Script, Frame, Mask, Bar.

Into layer bar, drag one instance of your content graphic symbol. Now, so this doesn't get confusing I'm going to refer to each area of content within your 'content'graphic as a 'scene'. My example above has 5 'scenes', with the numbers 1 through 5 on them. OK? What you want to do now is align the centre of scene 1 of your content, to the centre of the stage (it might help to use the Grid and Snap to Grid functions here, found under the View > Grid menu). The rest of your content should be off to the right of centre.

Now select the Frame layer and, using the rectangle tool, create an empty rectangle (no fill colour) that surrounds scene 1 of your content, like a frame around a picture (see graphic below).

Your timeline should look something like this (but with the Mask and Script layers also):

Now create a keyframe at frame 5 (select frame 5 and press F6). At frame 5 move the centre of scene 2 of your content to the centre of the stage (so that the frame now surrounds scene 2). Create a motion tween between frames 1 and 5, (right click frame 1 and select 'Create Motion Tween'). If you've done this right, you can press enter and your clip should show your 'content' graphic sliding to the left betweens frame 1 and 5 such that scene 1 moves out of the frame and scene 2 moves in.

Now you need to replicate this tween process for all remaining scenes within your 'content' graphic. When you've done this, press enter and you should see your content sliding from right to left across the stage wile all scenes pass through the frame. Don't worry, we'll get around to stopping them later. For now we just want a smooth motion between scene 1 and scene 5, (or your last scene, whatever number it is).