Protocol Translation is not the recommanded way of doing things. This is largely untested and unsuported by OS and routers.
It's better to get IPv6 from your providers. This is simpler and works.
Just for information, the IPv4 depletion date has been advanced to 2011-02-10 (february) according to Ipv4 Depletion site (
http://www.ipv4depletion.com/).
Ipv6 can be simply pushed through PPPoE over ADSL links. This is the way we give IPv6 / IPv4 dual stack to our ADSL clients.