Despite his works being relatively neglected during his lifetime, especially in the United States, there seems to have been a resurgence of interest in Mervyn Peake. This is partially because 2011 marked the centenary of his birth, but I also truly believe that many people are finally discovering his great genius.
This is by no means exhaustive, but here are a few resources that you might find especially rewarding if you are at all curious about Mervyn Peake, his art, his Gormenghast novels, his poetry, his stories or his life.
1) THE OFFICIAL MERVYN PEAKE WEB SITE: I believe this is administered, at least partially, by Peake's son Sebastian. This is the best place to start and contains a wealth of information including sketches and thorough descriptions of the characters in the Gormenghast novels, a beautiful selection of Peake's illustrations for other novels and a small collection of Peake's own paintings and drawings. A treasure.
2) THE MERVYN PEAKE BLOG: Again run by Peake's son Sebastian, this is the blog of the official Peake site. Updated fairly regularly with news about new publications, critical inquiry, and other Peake-related events online and off.
3) PEAKE STUDIES: For many years now, G. Peter Wittington has edited a biannual collection of criticism and debate of Peake's entire body of work titled Peake Studies. There is a great deal of information available at this site, and print copies of many of the previous volumes of Peake Studies are easily available as well.
4) THE BBC GORMENGHAST MINISERIES: While I have mixed feelings about the BBC's production, much of which can be previewed at that YouTube link, I do believe that they did the best they were able to with limited time and money. Ultimately, as someone starving for more explorations of Peake's work, I tend to be fairly forgiving and I do believe parts of this production hold up amazingly well. Take a look, and if you like what you see, the entire four hour miniseries is available on DVD.
Just a few links, I know, but that is a good start. Of course, there is no substitute for the books themselves, so by all means track them down and read them. Peake was a rare genius and his work remains a treasure.