the gcc package is 30+mb, so the others are just included (gjc, etc). so you only need the gcc401 or whatever, file.
well... search google.
why do you say not to? there would be an overwhelming number of results for compiling from source.
if your just lazy, then read this
tutorial on compliing/installing from source. the example uses a .tar.gz, so you might need to read this
so you know how to extract .bz2's
again, why not search google?