Installed an Epson Workforce 600 wireless printer over the weekend on my Mac and my wireless network. After doing all the normal printer stuff (loading ink and paper etc.) you connect the printer to your wireless router with an Ethernet cable (provided.)
You then have to install the software on your computer. Then it walks you through setting up the printer on the network. You need to know your network SSID No. and WEP key. If you have a wireless router from your Internet Service Provider, that info is usually with your install material or on the bottom of the router.
After the printer is found on the network, you disconnect the Ethernet cable and you are ready to go. You also have to configure your scanner on the network, but that is pretty much done on the printer. You do have to provide your computer with the IP address of the scanner, which the printer gives to you.
Whole process took about an hour and went very smoothly.