Input.GetAxisRaw
static function GetAxisRaw(axisName: string): float;
Description

Returns the value of the virtual axis identified by axisName with no smoothing filtering applied.

The value will be in the range -1...1 for keyboard and joystick input. Since input is not smoothed, keyboard input will always be either -1, 0 or 1. This is useful if you want to do all smoothing of keyboard input processing yourself.
	function Update () {
		var speed : float = Input.GetAxisRaw("Horizontal") * Time.deltaTime;
		transform.Rotate (0, speed, 0);	
	}