From their press release:
"Welcome to the Darwin Correspondence Project’s new web site. The main feature of the site is an Online Database with the complete, searchable, texts of around 5,000 letters written by and to Charles Darwin up to the year 1865. This includes all the surviving letters from the Beagle voyage - online for the first time - and all the letters from the years around the publication of Origin of species in 1859.
The letter texts, and the contextual notes which help make them accessible, are taken from the first thirteen volumes of the Correspondence of Charles Darwin (Burkhardt et al., Cambridge University Press 1985-). Letters from later volumes will be added on a rolling programme following behind publication of the print edition. Volumes 14 (1866) and 15 (1867) are already published and Volume 16 will be published in 2008.
The database also includes summaries of a further 9,000 letters still to be published. There will be 30 volumes of the print edition in total. Previously unknown letters continue to come to light.
Darwin’s letters are a rich source of information on many aspects of 19th century science and history; they are also very readable, and we hope they will be used and enjoyed by a wide audience."
Find out more about the letters and Darwin's correspondents here.