According to this
(en.community.dell.com/.../linux-driver-\
available-for-dell-wireless-cards.aspx) the drivers should be included in the
current version of Ubuntu.

The first thing to note: your wireless card is actually a Broadcom, perhaps the
4311. Dell doesn't actually make wireless cards. When you are running Ubuntu,
you can open Accessories/Terminal and enter the command lspci to display the pci
devices, and one line will look something like this:
0c:00.0 Network controller: Broadcom Corporation BCM4310 UART (rev 01)

This will work if you run the Ubuntu LiveCD, you don't have to install Ubuntu to
do it. You might even be able to connect to your network. In the top-right of
your screen, there might be a network manager icon, near the volume control. If
you right-click it and select "edit connections," then click on the wireless tab
and "add" you can set up your network. You need to know your router's SSID,
encryption type and password.