I'm wondering if there is a setting that I am missing that allows an Android phone to produce an audio notification (or even vibrate) once charging is complete. As is stands, whenever charging is complete the external LED on most phones (such as the HTC Droid Incredible) changes from orange to green. The use-case is when the phone is charging across the room or in another location that's out of sight.
I believe my phone vibrates when it's done charging, but I've never seen a setting for it. I'm certain you could set up a profile with Locale to notify when charging is done.
There is an app called Battery Charged Notifier that will just notify you when your battery is fully charged. It is free, but there is a "paid key" that adds some additional features, like setting your own notification sound.