Has anybody come out with a jailbroken app that could literally add mp3 files to your ipod music library right from the iphone? There have been plenty or times I downloaded a song, but got annoyed because I had to switch to a different app to play it. If there isn't an app for that, then is there one that reads your ipod music library, adds those songs itself, but lets you add custom songs too? Simply, I would like to be alble to play my ipod music library and downloaded mp3s from the same app (jailbroken or not, doesn't matter to me)

EDIT: oops I put this in the wrog category. This is not specifically for the iphone 4, but for any device.