What is a good way for me to download music from an app?

So I just got my iPhone 4S. Before that I had used the app music tube on my iPod. Loved it! Until, I got my phone. I looked on the AppStore and they don't have that app anymore. Does anyone know a good and free app to use that will download music and let me listen without Internet?

Gtunes

Do you know how to copy music FROM an iPhone? It's like all of you iPhone and iPod users are so hot to download directly to your devices, and then you end up losing all of your music because it wasn't backed up before it was lost, stolen, damaged, otherwise bricked up or needed to be restored.