Added usage instructions.

Manifest

@@ -1,6 +1,17 @@
-README
+CHANGELOG.rdoc
+LICENSE.rdoc
+Manifest
+README.rdoc
 Rakefile
 lib/domain_name.rb
+lib/domain_name/definitions.dat
+lib/domain_name/errors.rb
+lib/domain_name/rule.rb
+lib/domain_name/rule_list.rb
 lib/domain_name/version.rb
+tasks/domain_name.rake
+test/acceptance_test.rb
+test/domain_name_test.rb
+test/rule_list_test.rb
+test/rule_test.rb
 test/test_helper.rb
-Manifest

README.rdoc

@@ -41,6 +41,30 @@ Via RubyGems/Gemcutter
 
 You might need administrator privileges on your system to install it.
 
+
+== Usage
+
+Example domain without subdomains.
+
+  domain = DomainName.parse("google.com")
+  domain.tld
+  # => "com"
+  domain.domain
+  # => "google"
+  domain.subdomain
+  # => nil
+
+Example domain with subdomains.
+
+  domain = DomainName.parse("www.google.com")
+  domain.tld
+  # => "com"
+  domain.domain
+  # => "google"
+  domain.subdomain
+  # => "www"
+
+
 == Credits
 
 Author:: {Simone Carletti}[http://www.simonecarletti.com/] <weppos@weppos.net>