When you use the Internet, you really aren't using the names of websites or computers, you're using IP addresses, but since most computers use DNS, you can use a website name and DNS takes care of finding the IP address for you. Address Resource Records are placed in a zone file stored on an authoritative nameserver so that when the nameserver is queried with a hostname, it can answer with the correct IP address.
Address resource records provide the base hostname to IP Address resolution service provided by a DNS nameserver. An Internet Address record is configured the same way for all hosts; however, additional records may be necessary if the host being resolved provides additional services such as DNS or E-mail.
Web Servers
zippo.net. IN A 198.204.18.190 www.zippo.net. IN A 198.204.18.190
The example above allows both http://zippo.net and http://www.zippo.net to resolve to the same IP address. Most people, including most web hosting providers, forget to set this up. This makes accessing a web page easier on your customers. This can be accomplished another way using a CNAME record, but isn't necessary. See my CNAME tutorial for more information on what CNAME records are for and how they work.
User's Workstation or Standalone Server
zorba.zippo.net. IN A 198.204.18.131
Every computer that should be reachable from the Internet must have an Address record. Networks that are not directly part of the Internet also need DNS resolution if you want to use the computer's name instead of it's IP address to connect to it.
The Address resource record places the fully qualified domain name of the host on the left and the IP address on the right.
DNS Name Servers
zippo.net. IN NS ns1.zippo.net. ns1.zippo.net. IN A 198.204.18.131
DNS nameservers require an additional NS record. Note that if you have additional nameservers that aren't part of your domain, you do not use an A record for them in your zone file for your domain. See the namserver record tutorial for more information.