Dan Bernstein's djbdns site - http://cr.yp.to/djbdns.html

Life with djbdns - http://www.lifewithdjbdns.org

Another good guide to djbdns - http://enderunix.org/documents/eng/djbdns_installation_en.html

Qmailrocks.org - My installation guide for Qmail. Qmail runs great when coupled with dnscache.