N900 FM radio receiver
The N900 FM receiver allows the reception of broadcast FM radio signals using the headset/headphones as an antenna.
Hardware
The FM radio is part of the Bluetooth chip. It receives FM radio signals using the headset or earphones plugged into the 3.5 mm socket as an antenna (actually arbitrary headset/headphones, or any other cable, for this purpose).
Software
The FM receiver is implemented as a video4linux radio device.
The only (?) userspace application that uses the FM receiver is [FMRadio|http://maemo.org/packages/package_instance/view/fremantle_extras_free_armel/fmradio/2010.03.20/].