there are some Network tools in the administration or system
pull down menu in Ubuntu, at the top of your screen pull down menus.
You will have to see if your wireless card is recognized there first.
RA0 I believe is what you will be looking to enable. Ubuntu does not
automatically configure you wireles network cards for you. I'm at
work now so I don't have access to my laptop that I have Ubuntu, and
like you it is a Duel boot with Windows XP. I also have a plug in
PCMCIA wireles network card, a belkin, and I had to enable it with the
Network configuration tool in Ubuntu. A GUI menu tool.

After you configure you wireles card for the default network device
you will have to reboot Ubuntu.