This page provides links to other webpages or resources available if you are interested in Eberron. While I encourage my players to learn more about the world for their own enjoyment it is not mandatory to play the game and any player knowledge does not necessarily translate to character knowledge.
Bear in mind that my Eberron is not exactly Canon, for example the names and some stories about the Sovereign Host are different and I have worked in the 4th Edition Creation Myth as well as keeping the original Myth of the Three Dragons.
Keith Baker Website
Keith Baker submitted the original write up for Eberron as part of a competition to create a new D&D world. He has been heavily involved in the creation of all aspects of Eberron and his personal opinions, published on his site as Dragonmarks, flesh out the world with more information.
The Eberron Wiki
I find this page very helpful. Some pages appear to be specific to someone’s campaign but most of it is canon.
The Grand History of Eberron
Comprehensive history of Canon Eberron.