Linette - see my post just above yours. Almost all charging devices these days are self regulating - including car battery chargers. And iPhone chargers. The current is determined by the current draw - i.e. By the device being charged. The charger doesn't just keep pumping current into the device after it is fully charged. That's why you can keep your laptop connected to the mains power for days or weeks. It's not as good for the battery as cycling the battery charge down then back up is, but it won't damage anything.
You (and your kids) can safely leave your phones on charge all night - or even all week if you want to.
It is a good idea to cycle the batteries down to almost empty about once a month - pull the plug out of your laptop, or just leave the phone off the charger for a couple of days, etc. That improves battery life due to the nature of rechargeable batteries (even the newer lithium-ion types). But leaving things on the charger doesn't harm them unless it is a very old charger and device, before they became self-regulating. Also, most chargers are global voltage as well (110-240v) and will auto-sense what they're plugged into. That came in about the same time as self-regulating chargers. Pretty smart technology really...
