How do I get mingw-w64 operational?

[Simson Garfinkel]

Hi. I have a few "newbie" questions. I've been using mingw32 to
cross-compile Windows apps from Linux. One of my users requests 64-bit binaries and
I've been unable to get it to work.

1. Is there a repo that contains RPMs for mingw-w64 to allow me to use the cross-compiler
under Fedora FC15? (or FC14?)  I have spent significant time on this, but only the 32-bit
compilers get installed. Am I missing something obvious? Do I just need to compile from
sources?  If so, is there documentation on how to do that?

2. Once I get it installed, what's the "--host=" option that I provide to
configure scripts to make it produce 64-bit .exes?

3. What's the difference between amd64 and i586?

Thanks!