Place your text event on a track. Type a single line of type (your ‘ticker tape’) as long as you want – even if it disappears off the page. Using the placement tab place your text at the bottom but within the safe zone. Then place your curser over the text. It will turn into a hand. Move your text off the right side of the screen and set your first keyframe. Then move your entire text off the left side. The trick is keeping it at the same horizantal level. Then set the last key frame. When you play this your text will move from off the screen right, across the bottom and then off the screen left. If you stretch out the event it should repeat again and again depending on how long you stretch it out.
Good luck