Prevent iTunes from starting when iPhone/iPod/iPad is plugged in on Windows

"Have you tried disabling ""Itunes Helper"" (ituneshelper.exe) ?

It's a program launched at startup. To disable it, use msconfig or any program that helps with managing startup programs (Startup Control Panel for instance).

You could also use iTunesBooster (not free though). From their FAQ:

Why would I want to disable / delete
iTunesHelper?

iTunesHelper is a service used by
iTunes to determine when an iPod is
plugged in, so it can automatically
launch iTunes. The iTunesHelper
service unfortunately eats up a
non-trivial amount of your computers
available processing power - all of
the time, not just when iTunes is
running. iTunesBooster disables and
deletes iTunesHelper, thus removing
the significant performance impact
that installing iTunes may have placed
upon your computer."

"try running this as batch file when you log into windows - I use it for my iPod Touch:

@echo off
net stop ""Apple Mobile Device""
net stop ""iPod Service""
net stop ""Bonjour Service"""