I in the process of reconfiguring my network. It is currently like this:

internet - modem - wireless router - wired server/clients 
                          |
                          |---- wireless clients

but I need to move the router to get a better signal for the wireless clients. So, I'm looking at this:

internet - modem - server - switch - wired clients
                               |
                               |---- wireless router - wireless clients

How do I set up the server to enable this? Also, what set ups do the clients need.

The server is Ubuntu 9.04 and the clients are a mix of Windows XP / 7, Ubuntu and printers.

I believe this new set up will allow me to control access to the internet, which would be useful.