Well, I've got a simple NetGear router which cost me about £40... and it's more or less plug it in and watch it go.... with default settings anyway.

Any config you did want to do would be via a webpage running on the router itself... very simple and platform independant so your Mac won't make any difference. Once set up, the devices have a direct connection just as they did before...

Seriously it should work out of the box with a cable to your modem in the right connection point, and a couple of cables for your MAc and PS3... unless your ISP does MAC address filtering...