I used the MacOS X installer here: http://www.deepdarc.com/miredo-osx/
I've now uninstalled it* and am trying to use SixXS.net and AICCU (Automatic IPv6 Connectivity Client Utility) to get onto IPv6.
I've also gotten this to work:
1) Signed up for an account on SixXS.net.
2) Requested a Tunnel to a Point of Presence - That is a "a router/machine serving IPv6 in IPv4 tunnels.", essentially letting you push all of your IPv6 packets over IPv4 to that machine, which then transmits said IPv6 packets to the right places.
3) Waited a bit, until I got the confirmation email in my spam box that informed me that my tunnel was ready.
4) Download the tuntap virtual network interface for MacOS X here: http://tuntaposx.sourceforge.net/ (I grabbed, and am using tuntap_20080804).
5) Unzipped the tarball archive and ran the installer pkg inside.
6) Because this is for my laptop, and I float around, I opted to use the AICCU / heartbeat option (that is, as long as my machine sends a packet, they keep my tunnel up and running. It also lets me move from one IPv4 point to another without having to reconfigure things.) So I downloaded the AICCU source (http://www.sixxs.net/tools/aiccu/ - the MacOS X link pointed to an .exe file. WTF people?) and ran:
$ sudo make install
in the unzipped AICCU source folder. No issues installing
7) I opened up /etc/aiccu.conf and set my username (to my SixXS username), password, ipv6_interface gif0, and behindnat true (last one might not be necessary).
Then I ran
$ sudo aiccu test
to check to see if everything worked. There should be 8 total steps, which... should all work. I was getting stuck at step 5/8 for a while, until I realized that 1) I needed to be root, and 2) ipv6_interface should have been set to gif0
*It works perfectly. I just wanted to try my other option(s?).