sagood

http://www.latex-project.org/ftp.html
Linux
Your system distribution or vendor has probably provided a TeX system including LaTeX. Check your usual software source for a TeX package.
MacOS X
A full TeX system including LaTeX, called MacTeX, is available for installation with i-Installer. Download MacTeX.
Windows
Check out the proTeXt system; this allows you to install a full TeX system, including LaTeX, while reading about the basics of the installation. Download proTeXt.