Ah, now this is a very nice new feature in iTunes 7.
There’s more information here.
I’ve noticed a bit more of a trend in this direction recently: for applications to incorporate backup options for their own data. I think it’s quite a good idea, because they often have a better idea of what needs backing up, how often, and in what way, than a more general “copy the files” backup. A couple of other packages I use which have two very different, but both very good, backup strategies built-in are the excellent accounting package MYOB and Apple’s Aperture.
So my photos, my accounts and my music now all have their own backups in addition to the general disk-cloning that I do from time to time with SuperDuper. Good for one’s peace of mind. I shall now go to bed and sleep soundly.