Not exactly true, I just went back to iOS 4.3.3 from iOS 5 after I found out you needed to activate to use iOS 5 (D'oh!), all you do is enter Recovery Mode when connected to iTunes & it downloads & installs 4.3.3 & you just restore from a backup to get your stuff back EDIT: This was using a iPod touch 4G
How It's a combo of download links for Windows, Mac OS X (iTunes) & Mobile (iOS) You need iTunes (10.5 Beta 3) which is an Application to install the Mobile side of it. But if you say so, I just thought it made more sense to put it in here.