Wiring ESC units to allow for PWM control and then writing software to control the motors is not as easy as it sounds.
One does not simply mash propellers, cardboard and Weetabix together to make a quad-copter! Here is a, more considered than not, plan for the required hardware.
Quad-copters are becoming quite popular from £30 mini quad-copters to £3000 drones.
How about building your own? Seems worth a try!
A project all about building and developing a Raspberry Pi based Quad-copter.