I am running Windos 7 Professional 64-bit, and I could not get it to work. I downloaded the iTunes 10.5 beta from jailbreakzone, but I got my actual iOS file from the developer website. I am running OS X on a virtual machine (that's where I do my app development) and I was able to install it there after a few attempts (with errors) and restarts. But when I tried to do my restore from backup, iTunes wouldn't recognize my iPad for some reason. So instead, I did the restore from the Windows iTunes (I did a backup on Windows and Mac VM just in case) and it worked fine.
However, it did not restore any of my apps... 🙁
Strange setup, I know, but I just couldn't justify buying another computer just to make a few apps 😉