The world’s first IPv6 (new version of the Internet Protocol) test will be conducted on June 8, 2011. On that day, major websites and web services such as Google, Yahoo, and Facebook will enable IPv6 for 24 hours on their main websites.
According to Google, the test will affect less than 0.5% of the internet users. In addition, even if IPv6 will be enabled for 24 hours, the old IPv4 will continue to be available.
How you can test your IPv6 connectivity?
There is a Google page to tests your connection and detects IPv6 connectivity issues. You can also test your IPv6 connectivity by going here.