Today Cloudflare is launching an Automatic IPv6 Gateway. To enable it, sign up for CloudFlare or login to your account and visit your CloudFlare Settings page.

CloudFlare.com > My websites > Settings (pull down menu) > CloudFlare settings

You can choose two options: (FULL) which will enable IPv6 on all subdomains that are CloudFlare Enabled, or (SAFE) which will automatically create specific IPv6-only subdomains (e.g., www.ipv6.yoursite.com). You do not need to change any of your DNS settings. After it is up and running, you can test your IPv6 compatibility and get a badge for your site.

Cloudflare is providing the Automatic IPv6 Gateway for free to all CloudFlare users.