I have used a US Robotics USR8054 WiFi router as an access point. My android phone connects no problem, but my Xoom will not connect. The tablet simply cycles "scanning..." then just stuck at "connecting..." screen.
How to fix the WiFI issues with Xoom
1. Update your router's firmware to the latest version
2. Reboot your router. Hold the up volume and push the power until the Xoom reboots.
3. If the router uses WEP, disable WEP, re-enable WEP/WPA-PSK and then reconnect with your Xoom.