You can download Emacs releases from ftp.gnu.org mirrors. They are distributed as compressed tar files, digitally signed by the maintainer who made the release.
Pre-compiled binaries for MS Windows may be made available on a best-effort basis in the windows subdirectory of the above ftp site (as zip files digitally signed by the person who built them). See the README file in that directory for more information. Building Emacs from source yourself should be straightforward, following the instructions in nt/INSTALL, so we encourage you to give it a try. See How can I compile Emacs myself?.
The development version of Emacs is available from Savannah, the GNU development site.