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.
[Note: Martin appears most prominently about 7 minutes in, discussing the works of Jack Vance, and then at the 45:50 mark answering a few questions.]
The Westeros network consists of several different sites, including a forum and a wiki, for all your A Song of Ice and Fire needs.