The Family Records Centre holds English and Welsh census returns. You’ll find Scottish census records at the General Register Office for Scotland. All available censuses have been microfilmed, and you can order them through an FHC.
FamilySearch lets you search a transcription of the 1881 census of England and Wales for free (click on the Search tab, then on Census). Alas, you’ll have to pay to view the transcription for Scotland; you can access it on the ScotlandsPeople Web site or order it on CD along with the English and Welsh records.
Although it’s not free and it’s known to contain many errors, the British national archives’ 1901 Census of England and Wales Online <www.1901census.nationalarchives.gov.uk> can help you locate your British ancestors. You can search the index for free, but you’ll pay about 90 cents to get full details on a person and about $1.40 to view an image of the original census page.
Other census indexes are still works in progress. Ancestry.com is creating every-name indexes linked to images of the 1871, 1891 and 1901 censuses for England, Wales, the Channel Islands and the Isle of Man. Census images and indexes are part of the UK and Ireland Collection.
Sponsored by S&N Genealogy Supplies and the British Data Archive, The Genealogist <thegenealogist.sandn.net> hosts information extracted by the Census Name Indexing Project. More than 1,200 volunteers are indexing British census records from 1851 to 1901. To view an index for a county during a particular census year, you have to purchase a subscription; prices range from about $9 for three months to about $27 for one year.