Admittedly, it could be a lot of fun in the pub or at a party, but the iStethoscope app for Apple's iPhone should also be a valuable app for the medical profession too.Created by Peter Bentley Peter Bentley of UCL and originally selling for 59p, the app has already been downloaded three million times, but that number should be boosted further with news that the app is now being offered free. Indeed, 500 users a day are currently downloading it.Speaking to The Guardian, Mr Bentley said: 'Everybody is very excited about the potential of the adoption of mobile phone technology into the medical workplace, and rightly so. Smartphones are incredibly powerful devices packed full of sensors, cameras, high-quality microphones with amazing displays. They are capable of saving lives, saving money and improving healthcare in a dramatic fashion – and we carry these massively powerful computers in our pockets.'Whether you're a doctor or just curious, the app is available right now at the app store. Note that the free version comes with ads and lacks a few added features of the 'Pro' model. So that modest 59p fee might be worth paying.