Explored e-books at the World Book Fair, also Project Gutenberg. Great to have free access to complete text of books out of copyright, but limited number of students want to read these. Always good to have for reference purposes--check on things--way we are using Amazon and Google books now to check on character's names, settings, whatever.
Pay for downloads of ebooks? I don't know if my student population is ready for that yet. Our public library does have ebooks available for loans--limited number of student based options, and when I talk to the public librarians they have mentioned that most popular use is for technical books. I have yet to see students popping Sony's reader--is it called the e-reader?
PrintQ and other companies that print on demand will be huge. Libraries probably can operate more cheaply by printing and distributing materials as needed than by accessing, cataloging, circulating, and holding materials. Time to check for library research articles on that issue.