The DogEars Network, we do this (Score 1)

This is actually something that we (a group of undergrad students at columbia) are trying to do right now, with www.dogears.net: to bring a very effective online textbook exchange we've built, along with a bunch of other similar tools -- stuff that students could really use but hasn't been provided by university administrations for reasons already mentioned here -- to other schools. These things, when designed well (less than 10% are, and there have been many of them attempted) work REALLY well on a single campus, little promotion is required becase students' need for them is so high. But it promotion IS required, as with anything, and that's the problem. Usually, the creators are the only ones who have enough invested to be willing to get the word out about such exchanges, and that's why they always stay at their campus of origin. Because you can't make money with a textbook exchange (unless you turn it into the "evil enterprise" somebody else mentioned, thereby over time making it as useless as the university bookstore buyback system.) The whole concept is to cut out the middle man, and to create a useful/successful/beneficial exchange you can't become a middleman yourself.

We've got some really good ideas about how to make it work though -- to keep it free while making it attractive enough to people at other schools to run and promote -- and we're practically there, the project is gaining a lot of momentum, everythign's looking really good! If anybody is interested in more info, send me an email.