The current iPhone 3G uses the Broadcom BCM4325, which has an FM receiver.  However Apple have locked down its functionality; currently it will only receive short-range FM transmissions from the Nike+ exercise peripheral.  Of course, there’s no telling whether Apple will similarly lock down the FM capabilities of the iPhone 3.1; many third-party accessory manufacturers, who already offer a broad range of FM transmitters, will likely be hoping they do.

As for the WiFi n functionality, the newer Broadcom chip supports all manner of MIMO dual-antenna signal boosting and better reception.  There’s also a shared Bluetooth and WiFi receive signal path which should save power and space but not at the cost of signal strength.

[via 9to5 Mac]