I wonder why all the kernel compiling stuff is describred; for most (all) current distro's, IPv6 is enabled out-of-the-box.
There's an easy check for this: check if the file /proc/net/if_inet6 exists. If so, just do 'modprobe ipv6' (as root) and you've reached the same as after completing the kernel compiling stuff in the article.
And if you want IPv6 connectivity to the outside world, go to http://www.prik.net/stuff/ and run the newest script. Even if you're behind Alcatel / Thomson NAT, that script will take care of it.