If you're providing content or network services on v6 and you don't have both a Teredo and 6to4 relay, you should - there are more v6 users on those two than there are on native v6[1]. Talk to me and I'll give you a pre-built FreeBSD image that does it, boot off compact flash or hard drives. Soekris (~$350USD, incl. power supply and CF card), or regular server/whatever PC.
Pardon me for interfering with your lucrative business here, but anyone contemplating running a Teredo relay and 6to4 relay should first understand the capacity issues before buying a little embedded box to stick in their network. The ARIN IPv6 wiki has this page <http://www.getipv6.info/index.php/First_Steps_for_ISPs> which not only gives you a number of options for setting up 6to4 and Teredo relays, it also points you to documents which describe what these things do so that you can understand how to size them and how to manage them. And the ARIN wiki tries to be vendor agnostic as well. --Michael Dillon