IPv6 LAN -> IPv4 Internet

[Barry Commander]

Hi guys
I've found it very easy to get all the machines on my LAN speaking IPv6 but
would like them now
to be able to access the internet using IPv6 until they reach my router,
where it converts to IPv4
and relays the data to the internet, converting back to IPv6 on the return
route.
Is this possible? Where would I find the information required to set this
up?
Thanks a lot
Barry