Online digital book library for students

I'm after a online book library suitable for students aged 10 and up. I have been looking at Google Books which appears to be perfect if I can put a hyperlink on our school site with a personalised library shelf I have constructed myself. The only drawback is I'm not sure if 'outsiders' will be able to add comments etc to the books which appears to be a permanent feature of Google Books.

Does anyone know if Google Books is suitable or can you recommend an alternative?

Thanks in advance.

Jason McMahon