I have an iPhone 4 and i downloaded and installed iTunes 64 bit on my Windows 7 Ultimate (x64), and when i plug in my iphone, the computer recognizes (playing a sound), but it is not showing in itunes, i tried everything. Reinstalling, Restarting, ANYTHING else that the apple support says, no luck. BUT the funny thing is, i downloaded iTunes 32-bit on my dad's old notebook running Windows XP (x86), and immediately, after i plug in my iphone, it automatically pops up there, and i'm able to copy files, music, videos, and basically all the features available.