The Citadel is an archive of information for George R.R. Martin's A Song of Ice and Fire.
New to the series? Read our spoiler-free review of A Game of Thrones.
At Trinoc GRRM confirmed he has several publishers interested in the 3rd Dunk and Egg story he just hasn't settled "on the best venue" yet. He also said that D & E will be collected into a book and that all of the stories he has planned will not fit into one volume.
The Westeros network consists of several different sites, including a forum and a wiki, for all your A Song of Ice and Fire needs.