Well, that was fast.
A group of hackers, the Chaos Computer Club, claim to have already hacked Apple's iPhone 5s TouchID.
How'd CCC hack it?
They lifted a print from glass, brushed it up in a computer, applied the print to latex, put the latex on a finger, then touched a finger to the sensor.
In short, hacking TouchID looks doable with a lot of skill and effort. "Your fingerprint is a convenient way to protect the garden-variety secrets and shopping we all keep," says ZDNet's Ed Bot. "Combine it with a reasonably strong passcode and you should be perfectly safe. Unless you're also a character in a spy novel."
CCC also wrote a how-to on faking fingerprints with things around the house, here.