I have been working for a year on my home-made quad. It is made with wood, and it is controlled via wifi using a Fonera Router
Both WII NK and WM+ sensors gives the information to the router throughout custom CPU GPIO pins. To achieve I2C communication a especial linux kernel module is used to make an emulated i2c port with every 2 GPIO pins available.
Fonera sends rotor commands to a 16F876 PIC, which generates PPM signals to manage ESC ( Electronic Speed Controllers). Those ESC are the power stage to trifasic motors.
To achieve very fast and less time consuming requests, http router web server has been modified on it's source code, to process all the AJAX requests in a RAM shared memory portion on the router.
Software control is home-made, and suited to be run into Fonera. It reads nunchuck and motion+ wii sensors, applies a low-pass filter, and a 2ndcomplementary filter (The RoyLB implementation ->thnx!) on every loop which has been previously readed.
Now I'm testing better PID values...