Where can I get the GCC / g ++ compiler for my 64-bit Windows 7 machine?
http://www.google.com/#q=win64+gcc
No matter how often the download page moves, this should find it for you.
At the time of this post, the top result (and the correct download site) was http://sourceforge.net/projects/mingw-w64/
http://sourceforge.net/projects/mingw-w64/
Since then, the project has moved to http://mingw-w64.org/ , and you can find the Windows installation packages at http://mingw-w64.org/doku.php/download/mingw-builds , which is now one of Google's best hits.