assign its contentPath (as2) or source (as3).
and to customize the scrollpane, check the flash help documents:
Thanks for your reply.
I am using AS3 and I looked into the documentation and apparently Scroll Panes can only hold movie clips, JPEG, PNG, GIF, and SWF files. While I was googling I found a great tutorial on how to create a custom scrollbar from scratch so I'm going to go with that. Thanks though!
if you only want to scroll text normally, you might do better to use the textarea. if you wanted smooth scrolling and/or scrolling with easing, you would add a textfield to a movieclip and ease your movieclip (in a scrollpane, if that worked for you).