iTunes does have a higher resolution format, but it is not available for their whole library. Look for "iTunes Plus" designation at the bottom of the selection description in the catalog. You can also select to view an "iTunes Plus" only version of the catalog on the iTunes Store home page.
These files are 256kbps versus 128 - about 10MB per song.
MusicGiants is another good choice.
These files are 256kbps versus 128 - about 10MB per song.
MusicGiants is another good choice.