The following sites provide ongoing statistics about the adoption of IPv6:

• US NIST IPv6 and DNSSEC Statistics- excellent set of charts and lists related to IPv6 and DNSSEC deployment within the US government as well as estimates for industry and universities.
• Daily IPv6 Statistics at Vyncke.org
• Lars Eggerts’s IPv6 Deployment Trends – data from October 2007 to the present
• Google’s IPv6 Statistics page

Do you know of additional sites we should consider adding here?  If so, please send them to us.