Assuming that your server is running currently as a DHCP server, you'll either want to disable that, or disable DHCP in the router config. That aside, I am wondering what you have for an internet connection. Assuming that you have Cable/DSL/T1, you would attach that connection to the WAN port on the router, and then connect both the server and client machines into the router/switch. The uplink port, in the above situation, would be unused. Generally, FYI, the uplink port is 'shared' with the downstream port next to it, so if you had all of the downstream switched ports in use, you would be unable to use the uplink port. Note that not all uplink ports are shared, but my experience is that the majority of them are, at least until you get into a high-end router. You would, of course, be able to remove the hub from your network after both computers are connected to the router. Good luck, and if you have other questions, just post.

Thanks for you reply. It's a DSL router. I have this plugged into the WAN port. The uplink port has a switch, either uplink or standard port. I need to use the other hub becuase the router doesnt have enough ports. At the moment the server is plugged into the hub and the server is doing the DHCP. I wont to connect the Router with a little disruption to the network.
 
Also one other thing, after attempting a few things now my XP machine wont do DHCP with the server! I'm having to assign it all manually on this machine, DHCP simply doesnt find the server???

Is it safe to disable the DHCP on the server and just plug everything into the hub...then plug the hub into the uplink of the Router and get the Router to do the DHCP?

Ah, XP system restore has come in very useful on this occassion, DHCP is working after the restore. No idea what happened there.
 
Right this is the set up I have, tell me if it's going to work OK (waiting for ADSL to be enabled so cant test it)...
 
WAN connected to Router...Router's uplink connected to a port on the hub...DHCP on the Router disabled.
 
My XP machine on the hub can ping the Router...
 
So I guess it will all work ok now then right?

Sounds good... I agree with your decision to disable DHCP on the router, as that could possibly cause some headaches with the transition. Personally, I would run the hub off of a standard switched port of the router, and into the uplink port on the hub, that way you keep your uplink on the router open, you may need it in the future.

Trouble is, think I might have to enable the DHCP on the Router. Something has kicked out the DHCP on the server. I havnt touched the server at all, all Ive done is attach the router to the hub and enabled and disabled the DHCP on the Router, now when I disable the DHCP on the router the machines wont pick up the DHCP on the server. DHCP only works now from the Router!

Have you stopped the DHCP service on the server and/or rebooted the machine with the router acting as the DHCP server?