I am pretty amazed with some of the applications for iPhone, and how people get ideas to create them. This is one of them.

The iPhone Heart Monitor allows you to listen to your heart beats. Using the inbuilt microphone of your iPhone 3G or the headphone microphone, the Heart Monitor will pick up the rate of your heartbeats and display it. You can pick up the beats from pulse points at your neck, wrist, or when placed directly over your heart.

It works best with iPhone 3G, but you can still use it with old iPhone, but the inbuilt microphone does not detect heart beats. For best results you should use it in a quite places. One thing you should remember is that this is not a medical device and it might not be always correct. You can buy it for 5$ at hurl

via bluespark.co.nz