Alarm Clock v1.2
This is a widget that lets you use iTunes to gently wake you up in the morning. It lets you pick an iTunes playlist and set a time, and will start playing the given playlist at the given time, by slowly turning up the volume.
Currently, it does not support powering up or waking up the computer, so it can only be used with computers that are left on overnight.
Boki Seles has continued development on another version of this widget, with the name Red Alarm Clock.