Quadcopter motor control via arduuino help

I only need to be able to control motor speed from the arduino. However there are no escs in my drone. I'm not sure what to do. The motors are directly connected to the micro controller. Is there any way of controlling the motors by directly attaching them to an arduino or by connecting the arduino to the drone micro controller. Any help would be appreciated as i need to be able to have the motors spinning at specific speeds for a school project.

For a school project you can replace the controller by an Arduino, but don't expect that you can make it fly this way.

See BlueCopter: BlueCopter - Arduino Quadcopter - Exhibition / Gallery - Arduino Forum
BlueCopter is for brushless ESCs, but as it outputs PWM instead of servo signals, it may work with slight modifications.

Thanks a lot. I'll see what i can do

Also see MultiWii. MultiWii is an Arduino Leonardo with sensors, and you could probably find code to output just PWM.