Imac -> Airport Express Net Share



Am a newbie to macs so need a little tutorial or some pointers to the following dilemma.

I have the following setup:

i) iMac G5 with Airport card built in
ii) D-Link ADSL Router plugged direct to the Imac ethernet port
providing broadband access.

iii) Airport Express base station in living room

Heres the dilemma:

I have successfully setup base station in living room to play iTunes through theatre system.

However I plan to plug my Playstation2 into the free ethernet port on the base station.

I was wondering if the existing iMac wired connection could be delivered to the base station ready for me to connect my playstation.