Looks like this is somewhat dependent on their data center providers:<p><i>This will be a phased roll-out across the facilities, starting with immediate availability in Fremont, Newark in a week or so, followed by Dallas.</i><p>From the FAQ[1] page:<p><pre><code> Fremont, CA: Yes
Dallas, TX: Soon
Atlanta, GA: No ETA
Newark, NJ: About a week
London, UK: Q4 2011
</code></pre>
[1]: <a href="http://www.linode.com/IPv6/" rel="nofollow">http://www.linode.com/IPv6/</a>