[Hampshire] [OT] OSX and DHCP?

Hi All.

Sorry for the OT posting - but I know there are some *nix-aware people
here :-)

I've got some OSX Macs grabbing IP addresses from a DHCP server. I've also
got a local DNS server. These are not the same machine (and can't be,
either).

All the Windows machines on the network automagically update the DNS
server when they get an address. The Linux machine (mine!) can be told to.

I haven't a clue how to get the Macs to send their details to the DNS
server :-(

Any ideas?

Thanks!

Vic.