Just tested whether the Nokia E71 I use does IPv6. Yes, it acquires a global IPv6 address over wifi which can be pinged. And that is it. No application prefers IPv6, and in the first test a v6-only destination is unreachable. But.. this is an artifact of the connection manager I use (wuh?). The builtin browser can visit IPv6-only pages when I force it to use the home wifi. Normally I use a connection profile which includes 3G options and IPv6 makes the connection manager switch to 3G, with KPN not yet offering this. And dual-stack pages are still visited via IPv4. Same with putty for symbian: it only uses ipv6 when no A record is found and it can only reach the site when I force it to use wifi.