We just got a new Officejet 4500 that I began to set up last night. First I followed the recommended setup path for setting it up wirelessly: USB connection to my MacBook Pro, install the software, use the setup wizard, etc. It chugged away for a while and eventually I got back a bunch of errors "Failed to retrieve IP".
I have a wireless access point provided by my ISP which I have set up with WEP (no Mac filtering, no special firewall within the home network). After googling around for a while I decided to switch to WPA personal. I got my MacBook working with that, then tried the printer wireless setup wizard again. No go, same errors.
Next I tried setting it up (still with WPA) directly on the printer using it's menus. This also didn't work. The printer printed out a Wireless Network Test Report which looked like this in the Diagnostics Summary:
Wireless On: PASS Wireless Working: PASS Network Name (SSID) Found: PASS Security: PASS Printer Settings Consistent with Wireless Router Settings: PASS No Filtering: FAIL Connected: Not Run Signal Strength: Very Low Other networks detected matching your network name (SSID): No Downlink count: 2 Channel: Not Run
I also switch back to WEP and reran the setup via the printer menus, and failed the same way and got the exact same diagnostic summary.