Do not cast shadows (default).

	// Set light to not cast shadows.
	light.shadows = LightShadows.None;

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void Example() {
        light.shadows = LightShadows.None;
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def Example() as void:
		light.shadows = LightShadows.None