Well, there's no way I can properly explain the act here, suffice to say that any public authority (inc. branches of national and local government, the police, universities, schools, colleges, etc. etc.) has to tell you almost anything you want to know.

For a proper (40 page) guide, check out:  http://www.cfoi.org.uk/pdf/foi_guide.pdf

Also, people involved in ecological or animal rights campaigns should make sure they have, as well, an understanding of the (little known) Environmental Information Regulations, which cover virtually anything to do with 'living organisms' - and yes, that should include animals kept in labs.

Anyone been using the act at all? Any success?