The Nosgothic Realm, probably the oldest Legacy of Kain website still online, there you will find the original Dialogue for the games, artwork, fan fictions and other useful material related to the LoK saga.
Legacy of Kain: The Lost Worlds is a website that compiles all the cut material from the games including memorabilia, hacking tools, rumours and more. A catalogue of the things that might have been.
Home of the Enciclopedia Nosgothica, A Legacy of Kain fan site containing detailed descriptions of the games' characters, locations and creatures in an A to Z format.
The Legacy of Kain Wiki: a free source on all topics related to Blood Omen, Soul Reaver and the Land of Nosgoth that anyone can contribute.
All the essential information about Legacy of Kain in Spanish language, it also contains a detailed Timeline of the games.