The official list of all country specific TLD's, including .us, .uk, and .tv, plus links to where you can apply for a domain in that country. http://www.iana.org/cctld/cctld-whois.htm
Official web site of the DNS root servers. Information, including locations, ASNs, and IPv4 and IPv6 addresses, of the 13 root-servers.net systems. http://www.root-servers.org/
Paper discussing general name server security, with a focus on BIND. By Allen Householder and Brian King of CERT/CC. [PDF] http://www.cert.org/archive/pdf/dns.pdf
Offers information about DNSSEC: Security Extensions for DNS. Includes DNSSEC projects, articles, news, developments, presentations, howto's and RFC's. http://www.dnssec.net/
Information about the O'Reilly title by Paul Albitz and Cricket Liu. Includes the full text of Chapter 11 which focuses on security: TISG, firewalls, and DNS security extensions. http://www.oreilly.com/catalog/dns4/