For IPv6 tunneling within a site ISATAP might be a more adequate solution. See: http://www.litech.org/isatap/

Please note that you are creating protocol 41 tunnels. 6to4 uses protocol 41 packets, but uses the IPv4 address embedded in the IPv6 address to figure out what the remote IPv4 endpoint of the tunnel is. Why is the network not IPv6 enabled, what stops you? If you use true 6to4 then tunnels are created 'automatically' as the IPv4 address is taken out of the IPv6 address, you will have to use the IPv4 address of every host in the IPv6 address though, and then you get per host a /48.

Nothing really stops me from implementing ipv6, as the hardware probably can be updated if I invest enough time in it. But that is not a problem, I currently wish to experiment with 6to4 tunnels and want to try creating a few tunnels (got two testing Fedora 13 machines, want to make a dynamic tunnel on each) that will automatically find the 6to4 relay using the anycast address, but I haven't figured out yet how to do it. I probably want something like "ip tunnel add 6to4 mode sit remote any local x.x.x.x", but I am unsure how to configure the relay to accept the 192.88.99.1 anycast or if any form of special configuration is needed, but so far my experiments failed. Take note that I am a newbie to this so I do not know the exact kung-fu, but I wish to learn as it will surely come in handy in the coming years.