The main location for older Lancia information on the web is Huib’s site, Viva Lancia. It has extensive forums and many links. It has the most active classifieds.
For the Aurelia, there is the Registro Aurelia Italiano. There is also a site with excerpts from Bernabo’s definitive book on the Aurelia, and one on the B12 sedan..
There is another site with a fair amount of Lancia posting - DJ Richard’s Lancisti site, with its emphasis on Fulvias and Betas.
There is also a very complete article on the Aurelia (in Italian) on Wikipedia. Starting with the berlina, the site covers the B20 and other models. There is also another site on the 1950’s competition cars of Lancia.
For other Lancia models, there are good sites for the Flaminia , Flavia, and older models as well (Artena, Augusta). There is a serious lack of information on the key Lancia Lambdas or Aprilias. And for the commercials - one is forced to go back to the printed page.
For additional information, Paul Mayo (ex-librarian, English Lancia Club) publishes manuals on various models. His workshop manual on the Aurelia is the best, including many data sheets and club member’s observations. Huib (Viva Lancia) offers CD’s with scans of all the parts manuals and Owner’s manuals and the Aurelia information is very extensive.
For classifieds, see Viva Lancia and Omicron, for the British market fairly well. The American Lancia Club site has a few.
There are various forums that include Lancia, but only a few are listed. If you know of another good one, please let me know.
One site listed, VeloceToday, has very good overall Italian car info, mostly US based, but with some good European writing. Edited by Peter Vack, it has articles on Appias, Flavias, and most interestingly one on a test drive of a D50 and Appia based Dagrada Formula Junior. He’s even got a two part article on the B20, in good detail. On that site, check out the link to info on people, where you will find a neat article on Marcello Minerbi, who still has his father’s unrestored B12 sedan, owned from new!