Collection of Web resources about dig usage:

http://www.danesparza.net/2011/05/using-the-dig-dns-tool-on-windows-7/

http://anouar.adlani.com/2011/12/useful-dig-command-to-troubleshot-your-domains.html

https://library.linode.com/linux-tools/common-commands/dig

Download dig (part of Bind):

http://www.isc.org/downloads/

Some commands:

What is the website’s IP address ?

dig +short amazon.com

How to identify the name servers associated with a domain ?

dig NS +short anouar.im

What does the delegation path to my zone look like ?

dig google.com +trace

Which Mail Server is responsible for a domain ?

dig MX adlani.com

Which value is in cache in a given resolver ?

dig google.com @8.8.8.8

Which domain name is this IP associated with ?

dig +short -x 8.8.8.8

Which are the name servers of a TLD ?

dig +short NS nl.

When will the cache of an answer expire ?

dig google.com +noall +answer

Is the zone synchronized to all my NS ?

dig google.com +nssearch

Is a zone existing on this name server ?

dig SOA google.nl @ns1.nic.nl.

Using Dig to Retrieve Different Record Types?

dig srv _jabber._tcp.example.com