In general information about the availability of census records is to be found in GENUKI at the level of the separate countries making up the UK and Ireland - i.e. for England and Wales, for Scotland, and for Ireland. Here we just provide more general information related to the census.
Lumas, Susan. Making Use of the Census, The National Archives (2002) 128 pp. [ISBN 190336535x]
["This is a revised edition of this bestselling guide to census records at The National Archives. Census records are some of the most valuable and frequently used by family historians and the release of a new census every ten years is an eagerly anticipated event. Published to coincide with the opening of 1901 Census in January 2002, this new edition incorporates all the essential details for researchers wishing to exploit this new and important resource. It also offers practical advice to historians to find their way into the nineteenth century returns. It provides help in tracking down individuals as part of a family tree, and is equally helpful to social or economic historians. . ."]
A helpful tutorial on using census information, including advice regarding possible sources of errors, is provided on the British Genealogy website.
The Online Historical Population Reports project at AHDS History have a project to provide searchable online access all the census reports for Great Britain (1801-1931) and reports of the registrars-general (1836-1920) for England, Wales and Scotland. The current version is a demo version, but release version will be launched on 9th January 2007. Note that this site contains only statistical reports, and does not include information about individuals.
The British Surname Atlas CD allows exploration of the distribution of forenames and surnames in the 1881 census returns.