According to the iFixit teardown of the iPhone 4 (step 18 here), the iPhone 4 has the Broadcom BCM4329FKUBG, which has a FM tuner in it.
But who knows why its there? Because the iPhone 4 does not have a FM Radio app. Maybe its something Apple will activate down the line, maybe not, who knows?
The iDevice line has had FM tuner capable chip since the iPod Touch 2G and transmitter since the iPhone 3Gs. If Apple was wanting to enable the FM features (if they even exist) it would have does so by now.
The iDevice line has had FM tuner capable chip since the iPod Touch 2G and transmitter since the iPhone 3Gs. If Apple was wanting to enable the FM features (if they even exist) it would have does so by now.