See
Texlive page(http://www.tug.org/texlive/) for installing texlive.
See
Acuiring texlive(http://www.tug.org/texlive/acquire.html), especially getting
install-tl-unx.tar.gz(http://mirror.ctan.org/systems/texlive/tlnet/2008/install-tl-unx.tar.gz) tarball.
Unpack the tarball with
tar xvzf install-tl-unx.tar.gz under the unpacked directory.
cd to_the_unpacked_directory
sudo ./install-tl will give you installation option screen.
Then, take a look at the page,
Quickinstall.html(http://www.tug.org/texlive/quickinstall.html) at
http://tug.org/texlive/.
Take care of the path as stated in the above document: