We'll have one of these here at the office soon, so we can do a hands-on, but they're basically mini audiobook players that are ready to go out of the box. You pull a little tab to activate the battery and you've got a few hours of listening time. Once you're done, you're supposed to donate it to a nursing home or just but it on your bookshelf.
They're priced at about $40-$50, so they're not for the faint of wallet. However, the concept is pretty solid—pop into the store, pick one up, listen on the plane, drop it somewhere. Maybe a rental service a la Netflix is in order?
Product Page [PlayAway]