Ron's Intro to Parish Registers (PRs)

PRs of course are still being completed but they are basically the main research place for BMD prior to 1837 - see UK_BMD
Note: not usually Births but Baptisms (some registers also record birth) - a baptism may be within a short time of birth but could be months or years later.

Many churches are available on LDS (Direct to IGI) but not all - that is where the real research comes in - learn more from Genuki and perhaps join discussion lists for your areas of interest. 
Hugh Wallis has lists of parishes on LDS IGI with easy search - http://freepages.genealogy.rootsweb.com/~hughwallis/  (note IGI is not all churches)

More detail here http://www.british-genealogy.com/resources/registers/home.htm

9/2006 FreeREG search is now available http://freereg.rootsweb.com/index.htm - - NOTE no wildcards or soundex - search is exact.. FreeREG is a similar project for Parish Registers - as FreeBMD for GRO index - check coverage when there - BUT it is Free

very useful for 1780-1837 is Pallot's Index to Marriages and Baptisms
also http://www.britishorigins.com/ have various Index to Marriages including Boyd's - a pay to view site but you can search to check and you really should look at British Origins

County FHS usually have PR services - I know Oxfordshire has a lot of resources and I have some of their CDs - see English Counties

When looking for a parish always try a search in www.google.com 

Parish Locator is a download (a major tool)  now at http://www.parloc.pwp.blueyonder.co.uk/Frame.htm (was http://web.onetel.net.uk/~gdlawson/parfind.htm)

Perhaps you will find a PR here (recommended by someone - but I have not found anyone I wanted)  http://www.parishregisteruklook-upexchange.co.uk/index.htm

Burials
NBI  available for various counties on www.familyhistoryonline.net . This is the Federation of Family History Societies Pay per View site. You register and that is free and you can search free - and to see the record you pay if you want to..    NBI is availaible on CD also with some more counties BUT not a good coverage for London - try Cemeteries

check all also my page on English Counties

London Registers (London often looks like Middlesex MDX but also includes areas of Kent Surrey and Essex)

Simon Fisher has an very good and detailed page on London and Surrey registers
<http://www.sjfisher.pwp.blueyonder.co.uk/Def-London(Surrey)-Registration-Districts.htm#RANGE!A445>

see Pallot's Index to Marriages for special index 1780-1837 - similar also for baptisms .

David Hale not only has some great historic maps but he has one showing London parishes as in 1877 http://archivemaps.com/mapco/parish/parish.htm
a couple of clicks and you can find the area of St Olave or St John Horsleydown etc etc 

Brian Fisk's list of MDX parishes http://homepages.rootsweb.com/~bpefisk/fh/Middx/

http://www.westminster.gov.uk/libraries/archives/indexes/guide/guide15.cfm see also LMA Guildhall etc on London

London Docklands Ancestors specialise in the transcription of parish registers from the east end of London that were omitted from the IGI.. These are available to search online at http://www.parishregister.com and includes a map of all the East London riverside parishes

London Parish registers for which I have a CD from Archive Books but owner has retired and 2/2008 Ancestry say they will host

http://www.eastsurreyfhs.org.uk/ has CDs - Lambeth etc

London Churches http://www.touruk.co.uk/london_churches/london_churches.htm
Find a Church - The UK Church Directory http://www.findachurch.co.uk/
The Church of England http://www.cofe.anglican.org/ and http://anglicansonline.org/uk-europe/england/dioceses/southwark.html also http://www.southwark.anglican.org/parishes/ws2.htm

City Churches Map http://www.cityoflondonchurches.com/mappage.htm and http://www.steeljam.dircon.co.uk/churches/londonchurchlocation.htm

Victorian London Churches including Established Church (Church of England)  and Catholic (Roman) Churches  
see sections at http://homepage.ntlworld.com/hitch/gendocs/

Genuki on Middlesex churches http://homepages.gold.ac.uk/genuki/MDX/#ChurchDirectories and City http://homepages.gold.ac.uk/genuki/LND/parishes.html

and Genuki will have more information search their site or try google with yourparish genuki as also FHS sites so yourparish fhs

<http://members.ozemail.com.au/~pendoylan/Genealogy_useful_lists.html#List-opc>

Specific Parishes in which I have an interest as Mentioned in Source Documents 

• ST ANDREWS UNDERSHAFT
• St. Mary le Strand
• Rotherhithe St Mary with All Saints http://www.dswark.org/parishes/232f.htm
• Pictures of Old St Pancras - http://freepages.genealogy.rootsweb.com/~wemckenzie/church.htm
• Just to avoid any confusion, St Botolph Aldgate, St Botolph Bishopsgate, St Botolph Aldersgate, as well as St Botolph Billingsgate,are different churches, all in the City of London. These four churches and others are mentioned at
• http://homepage.ntlworld.com/hitch/gendocs/

Bow and Bromley are places that can lead to confusion try these sites for explanations 
http://www.eolfhs.org.uk/parish/bow.htm and http://homepages.gold.ac.uk/genuki/MDX/Poplar/churches.htm

Ron;s page on cemeteries mostly London but other areas as well