Zachary,
One of the powerful features of NLE is the ability to keyframe specific values of various parameters of a clip and change (animate) those values over the duration of the clip.
First, I'd recommend that you read everything in the manual on keyframing. For more detailed information and tips, pick up a copy of Kevin Monahan's book; "Motion Graphics and Effects in Final Cut Pro."
As Eric already told you, you can apply keyframes in the Viewer window. The specific animation you asked about is controlled in the Basic Motion section of the Motion tab (Scale, Rotation, Anchor Point, Center).
-DH
