Google is working hard to deliver 64bit version of Chrome web browser for Windows soon. The work is in progress, but there is no specific availability deadline so far. It would be first 64bit 3rd party web browser.
Google offered true 64bit Chrome for Linux last week. As source says, Google is focusing on x64 edition of Chrome for Linux and Mac OS X first and only afterwards to Windows. Testers can run 64bit Google Chrome on Ubuntu 8.04, 8.10, 9.04 and 9.10 from here.
It is already available in multiple releases for Windows including Chrome build 188.8.131.52 (Dev Channel), build 184.108.40.206 (Beta Channel) and 220.127.116.11 (Stable version).
You can download the most stable version for Windows Vista/Windows XP: