Godaddy: http://help.godaddy.com/article/668
Enom: http://www.enom.com/help/faq_dns.asp
Name.com: http://www.name.com/faq/create-my-own-name-servers
Network Solutions: http://www.networksolutions.com/support/how-to-register-a-dns-server-or-edit-a-dns-server-i-ve-already-registered/