The Home Sharing feature in iTunes 9 lets you share music between
computers right within iTunes, but it has a bunch of limitations. Both
machines need to be on one network, and the only automatic transfers
are new iTunes Store purchases--regular old CD rips and non-iTunes
downloads can be dragged manually from one computer to another.
iTunes 9 also added the Automatically Add To iTunes folder to your
iTunes Media folder. Any iTunes-compatible file dropped in here is,
like the sign says, automatically added to your iTunes library. Just
drop it in there and poof, it’s gone. But check in iTunes. It’s there.
iTunes 9’s Home Sharing lets you drag-and-drop content between up to
five computers on your home network after you tie each to your iTunes
Store account. SuperSync obliterates Home Sharing’s limitations,
letting you sync and share music and videos between as many machines as
you like, either over the local network or the wide-open Internet.