They have a short news article at http://www.he.com/news/article2.html.
The site to sign up for the service is at http://ipv6tb.he.net.
A good site with a LOT of IPv6 info: http://hs247.com.
Because it's a free service, Hurricane Electric doesn't spend a lot of resources supporing it. You're expected to provide your own support, including figuring out how to configure the darn thing.
For Linux: a HOWTO is at: http://www.tldp.org/HOWTO/Linux+IPv6-HOWTO
Another good source which also has pointers for IPv6 for Windows: http://www.ch.ipv6tf.org/documents.php
Now that IPv6 compatability requirements have been set in stone, expect to see a lot more interest (military, government, and public) in this.
Note: this does require some expertise (it's not plug-and-play).