Simple hidden system? iPhone controlled

[dracko]

I know very little about audio systems. So please bear with me, I currently just have the factory AM radio. I'd like to put an amp under my seat with a couple speakers under the seat that I can control entirely from my iPhone. Is this possible or do I have to have an actual head unit with a face plate and remote?

I'd be cool with just laying and aux cable on the bench seat but a Bluetooth amp would be cool too. Any advice on what to buy is appreciated.