If you can connect to a wireless network at school you could use a wireless network camera like this:
http://www.newegg.com/Product/Produc...-031-_-Product

As for turning it off if things go wrong. You can try something like a wifi enabled outlet adapter. These will allow you to turn outlets on and off via your smart phone.
http://www.amazon.com/WeMo-Insight-E...ds=wemo+outlet