The windows installer is only
available on the CD version, and it says right there on the download page http://www.linuxmint.com/download.php
IIRC, it may even only be available on the 32 bits version. But I wouldn't know, I don't use Windows at home...
There is a version of mint4win for Mint 12 ot github, so I guess in the final release there will be version of mint4win on one of the install media.
Mint 12 final will be released when ready
From the recent blog
, it sounds as it will release shortly.