Was gone for a few days. First question would (and I'm sure you've done it lots) is to check the IP of your router. If you can get to 192.168.0.1 from XP wired you should definitely be able to do it from ubuntu wired. Also check the wired connection on ubuntu overall. Again, if you can get to the 'net wired on ubuntu, we've eliminated the NIC/drivers.
I'm speculating your router uses a web interface to configure it. Check what protocol it's using (is it regular, HTTP or HTTPS). If it's the latter, be sure you can access HTTPS on ubuntu. Just to clarify, are you able to get to the router wirelessly on ubuntu? What about XP?
kvprajapati commented: Good question indeed. +11