Watch this YouTube video to get a peak at Boopsie for Libraries.
First time I've seen an iPhone app for libraries. Boopsie looks really cool and it's probably coming to a library system near you. Probably a bit much for schools but something like this will be available soon for schools as well.
There are also apps for Android, BlackBerry, and Windows Mobile platforms.
Other videos show Boopsie at Indiana University Libraries and on WorldCat.