Don't know what kind of router you have, but this may help:
I just bought an Epson Artisan 800 and figured out how to get it to connect wirelessly (I have a DLink wireless router and learned some time ago that I had to enter the MAC address of any device I wanted to have work with the router):
1. First I set it up according to their instructions/install CD with a USB cable connected to my iMac.
2. Once it was all functioning, I checked under "Network Settings" on the printer and copied the MAC address and printer's name as listed.
3. Went online to DLink and entered the printer's name and MAC address and assigned an IP address.
4. Turned on printer, connected it to the router (was recognized immediately), and followed directions in Epson's Network install guide installing driver on my Macbook Pro.
5. Able to print test page / works great with both Macs.
6. One disappointment: Epson Scan does not work wirelessly - must be connected via USB cable.
Add: oops, I just realized you have an airport extreme - I've never had one, but maybe it also requires adding the MAC address in order to recognize it?
Message was edited by: Barbara Daniels1