FreeREG. The objective of this site is to provide free Internet searches of baptism, marriage and burial records that have been transcribed from parish and non-conformist registers (parish registers and Bishop's Transcripts) of the UK.
This is an ongoing project which currently (Feb.2009) has approximately 1 million marriages, 4 million baptisms and 2 million burials listed. These are updated monthly. Coverage is patchy since data entry is dependent on permission being granted by the copyright holder. This means that Norfolk, at one end of the scale & for which permission has been given, is inputting thousands of entries per month, whereas many counties have little or no input.
Information supplied is very detailed with some transcribers adding comments in a notes section that they feel will be of assistance to a researcher.
For a list of parishes completed (wholly or partially) see the relevant county page eg FreeREG-Norfolk.