chickn's dashboard

As far as I know you cannot automatically re-order them. However, if you want to manually do it, you can.

Click on one of your apps and hold down. When all your apps start to shake and wiggle, you can let go. You can delete any unwanted downloaded apps in this mode. You can also click and drag to re-order all of your apps, even changing the four on the bottom. When you're done, just click the little round button to return home/normal mode.