There are some results of research into students' use of information, on a new website - principally students' use of textbooks. The research was carried out on behalf of the Publishers Association. Frustratingly, it doesn't say anything much about the methods or sample used in the survey, but the results are of interest.
http://www.openbooksopenminds.co.uk/default.htm(Photo by S. Webber: Cape gooseberry and Rudibekia, Hailsham, Oct. 2005)