Apple is expanding the range of material it makes available for educational users through the iTunes Store.

iTunes U - the educational are of the service - already provides a mass of free education content, including lectures and videos, from US learning institutions.

Apple has offered the free iTunes U service to universities since 2006 to distribute their course lectures or other digital content. Schools decide whether to make these materials available free and public, or limited to students only.

Half of the top 500 US schools already use the service to distribute their digital content to students. School's can open all or part of their site to the public, from alumni to parents to anyone with a love of learning.

"We found that there's a lot of educational content from other parties, and we thought it'd be a great opportunity to leverage iTunes U," Eddy Cue, Apple's vice president of iTunes, told Business Week.

Apple began "Beyond Campus" this week, starting with six partners, including public radio producer American Public Media, Smithsonian Global Sound, The Museum of Modern Art in New York, and KQED public radio and television in San Francisco, Cue said.