Hi dkriz
I looked at some of the iphone fft implementations and they look really good. There are some open source apps, but I didnt see any for an fft. The iphone appears to use some flavour of ARM processor so there will be a level of compatibility with the NANO. The specialist iphone libraries may not help with the simpler NANO. Lets see what people come up with - exciting stuff. I am trying to do something similar with an MBED development kit, but its a long way from being able to display like those iphone apps.
Tony