Infinite Disorder

Linksys describes this devices as a “Wireless Gaming Adapter”, however it can be used in a way similar to a traditional wireless bridge.
In my example, my access point has the IP address 10.18.18.1 and NATs IPs 10.18.18.0/24.

First, there are known issues with the older firmwares and something I’ll call ‘MAC address impersonation’. Without this functioning correctly, you shouldn’t attach a switch. First, upgrade your firmware to the latest, in my case 1.0.5:
Reset your WGA600N to defaults by putting a paperclip into the reset button on the back and waiting for the orange light.
Plug you laptop into the LAN port and give yourself the IP 192.168.1.100, 255.255.255.0
Navigate to http://192.168.1.250 leave username blank, password is admin
Tools->Firmware (upload firmware)
Tools->Admin (change password) 
Basic->Wireless (setup connection to wireless and security)
Basic->Network Settings (give it a new IP in the range of your access point, this won’t be the address of your multiple devices but rather an administrative IP; in my case 10.18.18.250) 

Now you should be running the latest firmware, plug an ethernet cable into the WGA600N and the uplink port on your switch. Plug your client devices into the switch and set them to dhcp (or static in your access point’s IP range, in my case 10.18.18.0/24).