Re: How do I shutdown to a command prompt?
In a terminal window, type "sudo /etc/init.d/gdm stop"
You will then need to press CTRL-ALT-F1 to get to the first text screen (actually, any of the first 6 functions keys will probably give you a login prompt)
Log in, and install the driver from there. I find typing "sudo bash" will prevent any odd behaviour caused by Ubuntu using the dash shell by default.
Once the driver is installed, you can start X again by entering "sudo /etc/init.d/gdm start", or just reboot ;-)
You will need to make sure you have various packages installed to compile part of the driver. iirc, the packages you need will be installed with "aptitude install build-essential linux-headers xserver-xorg-dev", though you may need to check on that - try it and see if it works.