There is a comprehensive set of web pages here on British-genealogy.com with lots of information about censuses, together with examples.

 * Census dates
 * PRO references
 * Registration Districts
 * What are census Pieces and folios?
 * Census Household Schedules
 * How was the census carried out?
 * What information is on the census
 * ....and lots more

http://www.british-genealogy.com/res...nsus/index.htm