I use the application called Best Baby Monitor from Martin Man. This app turns my iphone and ipod into a full screen video baby monitor with nice clear sound. You can also use ipad or mac in any combination. This application has also some additional features such remotely played lullabies, talk to baby from parent unit or night light. I use this app every single day and works perfectly! .. and costs only 4$ :)
https://itunes.apple.com/us/app/best-baby-monitor/id432791399?mt=8