nameservers sharing IP

[Jaunty Edward]

Hi,
i wanted to ask if there is a way by which Nameservers can share a IP,
I have seen many hosting companies giving nameservers for a low
ammount How can they do this if there is a limit of IPs in the world,
I am sure one day we will be left with no IPs,
So it will be nice if any one can tell me can nameservers share IPs
and if yes then is there anyway to find it out who is sharing what.


Thanks
Regards
Jaunty Edward