Apple has started to air a new commercial for the fourth-generation iPod touch. Entitled “Share the Fun,” the 30-second spot shows a number of middle- and high-school aged kids using the device to text each other over iMessage, video chat over FaceTime, play online multiplayer games using Game Center, update Twitter, listen to music, and record video, while the song “Tongue Tied” by Grouplove plays in the background. Notably,…