Here's a video of a nano quadcopter named Crazyflie that me and my two fiends +Tobias Antonsson and +Arnaud Taffanel did. The project is open source and designed with development and hackability in mind. It's also developed using only open source tools. Have a look at our page +Bitcraze or our website www.bitcraze.se
+Zac Thomas It's a kit so it has to be assembled. Here's a video showing the assembly so you can judge for yourself. Other than that it's just installing some software, plugging in a joystick (preferably a PS3 controller) and then you're ready to go.
+azeem sheriff If you want to use the Crazyflie there's an expansion header where you can connect your own hacks. Using this you could connect a Bluetooth 4.0 LE module and that would enable you to control it directly from your Iphone if you add firmware support for it.