The World IPv6 day is happening on the 8th of June 2011: major web sites (including Google, Yahoo!, Bing, YouTube, Facebook, …) will enable IPv6 by default for 24 hours.
Is you organization ready? You have better to check even if you run ‘officially’ only IPv4.
To test the client part (when your users will access the Internet): http://test-ipv6.com/ or http://ipv6eyechart.ripe.net/
To test whether your dual-stack web servers are well configured: http://ipv6-test.com/validate.php
Happy V6 World Day!