Do you know PIC's ? This is an ideal task for PIC, really cheap and simple.
:shock:
Why use a PIC it woudl just be a wast of its processing power! totaly pointless. of course you could use a PIC if you want, it will do the job. but u'll have to get a programer and learn the programing language.
an easier way would be to use a simple comparitor circuit, use an op-amp.
when the input voltage goes higher than 10V, the output goes high (or low depending on how you wire it) and all is good.