All the music bought in the iTunes store used to be in .m4a format. Now I just noticed that with the latest batch of music I got from the store, on my iPhone it is in .aif format and on my iPod it is in .m4a format. They are the same songs on my iPhone and iPod and the music on both devices came from the store. I did not do any converting and I did not use iTunes on the computer for any of it. I downloaded it all directly from iTunes on the iPhone and iPod. Anyone know what's going on?