Have you noticed these Playaway digital audio books in the bookstore lately? Yesterday I ordered twelve of them for my library (the titles were selected by the library's subject specialists). I have seen them at Borders, but the cost (about $30.00 and up) was a bit steep for me, so I have refrained from trying them out. They are essentially compact books on tape, but the book and the machine are all inclusive--a sort of disposible audio book. You simply put in batteries to listen.
I have long wanted an iPod, and I think they are not terribly expensive, but I have never gotten around to buying one. I always think it would be a great way to listen to books on tape while I am out walking (I don't like dragging around a portable CD player--too bulky--but I like the compactness of an iPod). Although I don't think I would ever buy one of these (better to have an iPod), I think they are a great idea for libraries. I'm not sure about reusing the earphones (maybe they can easily be cleaned off?), but otherwise I plan on giving them a try. Although I think these are really marketed for the general public (so not terribly academic titles) and probably would suit a public library more than an academic one, we are getting titles that are more reference related--books on pronunciation, several on learning languages, a few children's books, and one lone classic. I plan on borrowing the classic, My Antonia by Willa Cather and also one of the children's titles (well more YA really), Eragon by Christopher Paolini. I have always had mixed feelings about audio books (a good narrator in my experience is really important), but I am looking forward to giving these a try.