Parish registers online
585,000 Cambridgeshire baptisms and marriages are included in the IGI at FamilySearch but not all parishes are included (you can see the coverage here).
There are transcriptions of 418,000 baptisms, 242,000 marriages, 103,000 banns, and 335,000 burials at findmypast and about 120,000 baptisms and 18,000 marriages at Ancestry.
The volunteers of FreeREG have transcribed some of the registers for about 88 Cambridgeshire parishes. There is currently no OPC project for Cambridgeshire.
Cambridgeshire Family History Society has an online index which allows you to search over 4 million names in the records that it has published (these include censuses as well as parish register entries); many parish records are available on CD ROM, although these are typically quite expensive (about £20 for a single parish). The free search results do not indicate whether the entry is a baptism, marriage, or burial.
Births, marriages and deaths
Registration districts in Cambridgeshire
The Local BMD Indexes show the name of the spouse for all marriages, and the age at death for all deaths.
Balsham 1811, Cambridge St Benedict 1749, 1815, 1821, Cambridge St Edward 1801, 1811, 1821, Cambridge St Giles 1760, Cambridge St Mary the Great 1801, 1811, Cambridge St Peter 1760, Downham 1821, Duxford 1821, Ely St Mary 1801, 1811, Gamlingay 1798, Girton 1801, Great Abington 1686, Hildersham 1810, Hinxton 1802, Landbeach 1781, 1798, Little Wilbraham 1801, Melbourn 1831, Trumpington 1786, 1811, 1838
Reproduced courtesy of Francis Frith.
Key Cambridgeshire resources<! County record office, family history societies etc>
Cambridgeshire includes the Isle of Ely, which until 1837 was a county in its own right under the jurisdiction of the Bishop of Ely. Modern day also Cambridgeshire includes the historic county of Huntingdonshire (see separate forum).
Cambridgeshire Archives is based in Cambridge; there is a research service for those who are unable to visit (the cost in April 2013 was £10 plus £10 per half hour, maximum 2 hours). The archives hold many key resources including most parish registers for Cambridgeshire and the Isle of Ely, various pre-1841 censuses, and Quarter Sessions order books for Cambridgeshire 1660-1971, Cambridge Borough 1733-1945, and Isle of Ely 1801-1971.
Cambridgeshire Family History Society meets in several locations including Cambridge, Girton and March. Research surgeries are regularly held in many other locations.