Videomaker – Learn video production and editing, camera reviews › Forums › Technique › Editing › Text/Title zoom-in options on CS4 › You need to learn keyframi
You need to learn keyframing, you can adjust the Motion Properties (Scale and Position) with keyframes.
There is an article on Basic Keyframing here http://muvipix.com/products.php?subcat_id=41
It is for Premiere Elements but the process is almost identical. There are other tutorials and articles as well.