Google has several websites that are available over IPv6. Unfortunately, unless your ISP's DNS server is on the Google whitelist you are restricted to IPv4 (except for ipv6.google.com), even if you have IPv6 connectivity from a tunnel provider such as SixXS or Hurricane Electric.
There are two ways around this:-
1. Change your DNS server to one that is white-listed by Google. Both SixXS  and Hurricane Electric  provide servers for their users.
2. Manually add the addresses to your hosts file (/etc/hosts or %WINDIR%\system32\drivers\etc\hosts). I maintain a list of the addresses at .
 http://go.chaz6.com/8Aj or https://spreadsheets.google.com/a/chaz6.com/ccc?key=0AlcGce6kDLZIcHh4cl9hNU81dTA0dXFQSXdNWEFRRUE&hl=en