So I've installed the basic desktop version of Ubuntu which detected my wireless card immediately and there were no issues. I then installed XBMC and set it to the default session and there is no wireless connectivity. I've modified the /etc/network/interfaces as follows:

auto wlan0
iface wlan0 inet dhcp
wpa-driver wext
wpa-ssid <my_ssid>
wpa-ap-scan 1
wpa-proto WPA
wpa-pairwise TKIP
wpa-group TKIP
wpa-key-mgmt WPA-PSK
wpa-psk <oversized hex key>

When I restart the networking (sudo /etc/init.d/networking restart) I keep getting: "wmaster0 unknown hardware address type 801" and DHCP is unable to connect to the network... yet under GNOME I have no issues.

... help...

a well kept secret is to run your key through wpa_passhrase

wpa_passphrase my_essid my_key
It will return you an even longer version of your key. Keys can be too long, you know.

It also strikes me that it should never look at wmaster0, but wlan0.