Benoy Family Probably the best online genealogy research site for census, civil registration, passenger lists and so much more. You can do some searches for free and can sign up for a 14 day free trial (you must provide credit card info which will be billed if you do not cancel by the time the 14 days are up).
FreeBMD Totally free Civil Registration Index
FreeCEN Totally free Census Lookup - data is not complete but, if you don't have a subscription to it may be worth checking.
Family Search The LDS on-line presence. This site allows you to search the IGI and some census
GenUKI Great reference to find out what physical reference materials are out there and where to find them.
Alan's Cornish Pages
Family Tree Maker This excellent genealogy program is designed to work hand-in-hand with
Cornwall Online Parish Clerks This site has a searchable index and is worth checking since it may contain data which may not be available elsewhere.
Helm's Genealogy Toolbox
Eastman's Online Genealogy Newsletter
UK National Archives. This site contains searchable military records. Some documents are available for immediate download.
UK General Register Office Order birth, marriage and death certificates on-line.
World Vital Records Newspaper articles, gravestones, tec for the USA.