It came with Firefox 2.0 installed but I want to upgrade to 2.0.0.1. I downloaded the tar.gz file for the latest Firefox, but now how do I install it?
In general, how do you install and/or upgrade programs in Linux?
Ususally with a package manager that handles the format the software packages are delivered in (rpm, deb etc...)
What you d/l'ed was a compressed archieve file. It could contain anything -- the software could be already placed in package format (in which case you could just extact the files and then use your regular package manager), or it could be the source which you would then have to build yourself (./configure, make, make install)
For something like Firefox, stick with the packages that are found/available in the various software repositories for your distrubution
With Ubuntu, if you don't want to use the cli, you can use the synaptic frontend to apt.
You should also look into Automatrx or EasyUbuntu to help bring your system up to speed really quick and easy .... i.e. installing support for proprietary codecs etc etc.
Also, I know Ubuntu has some pretty good Wiki documentation and user forum