Do _not_ install the driver manually on Ubuntu.
Use the packages provided by your distribution. If you have really good reasons to do a manual installation, read
for a how to. There are several packages you need to install (developer tools such as the gnu compiler collection, kernel headers ...), and some steps you have to follow precisely, else your graphical user interface will be broken.
Please also keep in mind that after each kernel update (which is part of the updates you do regulary on an ubuntu system) you have to re-install the driver, else your graphical user interface will be broken. (Either no X at all, or failsafe)
And many people, here and in ubuntu forums, simply don't support people who broke the system
by manually installing a driver.
Please consider installing the packages provided by Ubuntu, or with Envy.