Most current distributions such as Ubuntu, Debian, Fedora, etc will allow the use of a USB WiFi network. First, run a LiveCD version of the OS, plug in the card (or plug it in and then boot from CD), and you should be able to use it. If you can, then install the OS, boot from hard drive, and use the WiFi dongle as you would any network interface. The Gnome desktop on Ubuntu has a network manager tool on the top menu bar. If your WiFi access point is encrypted (WEP/WPA), then you will have to tell the connection tool the passphrase or key to use the first time you connect (or each time when booting from a LiveCD). In any case, this is not an uncommon situation these days, especially when installing Linux on laptops. Even though most have a hardware ethernet port, they are often unused.