Transition

[Tim Larder]

Hi,
I have been reading through the relevent RFCs on migration and deployment
methods for IPv6. I was wondering in the future when IPv4 addresses have
completely run out, how will it be possible for a small organisation only
using IPv6 (because they are unable to be assigned any IPv4 addresses) to
communicate with IPv4 only nodes.
Also, why should IPv6 over IPv4 tunneling be used as opposed to using dual
stack nodes, using IPv4 when packets are required to be sent through IPv4
routers or networks ? Is tunneling used to maintain functionality of IPv6
packets when they reach the end node ?
Thanks
Tim