I've managed to do it on my Win 7 64 bit system (see my earlier post).
I uninstalled Bonjour first (using Microsoft Fixit because Control Panel Uninstall would not do it).
Then reinstalled latest version of iTunes. Then installed iCloud Control Panel.
iCloud works, but I have a couple of problems:
a) Everytime I restart, I get an Apple program that needs User Account Control permission to run (even though I've set the privileges to Adminisatrator)
b) I have 2 users on this PC. Using Photo Stream, one user uploads and downloads fine. The other can upload but can't download.
n.b. I am not using iCloud as a substitute for Outlook functions, only Photostream and Reminders
I have been having problems with iTunes and Outlook when I install iCloud on my windows 7 64bit
Everytime I installed iCloud, it would not let me open iTunes or outlook and the computer would freeze.
so i had to uninstall iCloud to allow me to work outlook and iTunes
However after weeks of trying different advice - none would work UNTIL if you uninstall bonjour from your windows 7 64bit and then re install iCloud - this then works