Sir Christopher Wren's Family : Ancestors and descendants of Sir Christopher.  According to this site there are no living direct descendants of Sir Christopher Wren.

Wren Genealogy : Site dedicated to Wren family histories.

Descendants of Abram Wren : Indented list of many descendants of Abram Wren.  It doesn't say on the site but I believe that the Abram mentioned here is from the Keswick area of Cumberland (now Cumbria) in England.  I've not yet managed to link to this family but the chances are that my line of Wrens is linked to this line, being in the same area at the same time.

Cumberland Bishop's Transcripts :  Very useful reference covering several Cumberland parishes in the 18th and 19th centuries.  Includes Dearham parish where many Wrens are to be found, including some in my line.

GENUKI - UK and Ireland Genealogy : Lots of help and reference material for the British Isles.  Access to local and surname research organisations.

Rootsweb : The parent site of the hosts of this site.  Masses of useful genealogical sources, forums and resources.

Familysearch : Massive genealogical site run by the Church of the Latter Day Saints (Mormons).  Includes the International Genealogical Index and the 1881 British Census. 

UK Public Records Office : The UK's main family records office.  Contains the 1901 British Census.