I have yet to work on my own biography, until then here are two biographies and some other web sites.

Biography by Stephen Rud
The complete Frank Herbert biography by Tim O'Reilly!

My notes from Dreamer of Dune by Brain Herbert as of May 2004

Other biography web sites:
The Templeton Gate
Fantastic Fiction
Frank Herbert Lives! article by Byron Merritt
Books and Writers
The Frank Herbert Memoral Sunset Watch
sffworld
Wikipedia
Interview with Frank Herbert