Fade In and out when level is loaded

Hello, I'm useing this script to load levels.

 #pragma strict
 
 function OnTriggerEnter () {
     Application.LoadLevel("Level-3");
 
 
 }

I was wondering how can i fade in and out when a level is loaded. (eg. when you walk into the tigger to LoadLevel the scene fades in and once the new level is loaded it fades out.)

Thank you for your time and help.