Hi, This is weird. I have a USB device phone service called Magicjack ( phone over the internet ) Diffrent people in my contacts list tell me I keep calling them and when they answer nobody is there and instead a song is played for them ( all the songs they hear are in my ITunes library ) I am not calling them and am not even home alot of times when these calls are made. I live alone so no one else is doing it. What do you make of this? ( No wonder they call the thing Magicjack!)

Don't know anything about it, but they do have some support
http://www.magicjack.com/2/magicfix.asp
There is an update for Vista there

sounds like a computer virus to me. If I were you i'd do some google searches about your USB thingy and viruses and those kinds of behaviors.