Now that we have a nice little touch-up brush with iPhoto2, it would be to be able to zoom in on an area instead of the center and then moving to where we want to edit. Now we can!
When you have your photo in edit mode, click and drag to select an area of the photo. Now hit zoom, and it will zoom in on the selected area instead of the dead center of the picture.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030203051416354