A few things to look at.
1. open add/remove programs from the control panel and make sure apple mobile device is installed.
1A. If not uninstall apple software update, itunes, and quicktime. Then reinstall itunes.
2. with the iphone connected, open computer management, look under services and make sure apple mobile device support is started.
2A. if you try to start it and it stops with a message that some services stop because there is not a task to perform, then you have software loaded on your computer that is blocking that service. This link from the apple support website might help out.
http://docs.info.apple.com/article.html?artnum=302538
3. If previous fails and windows only wants to load the camera driver for the iphone then open device manager right click on the iphone that shows up under imaging devices and uninstall.
3A. disconnect the iphone and reconnect. When windows detects new hardware, do not let it automatically install the driver. try to force windows to load the driver from c:\windows\system32\drivestore\usbaapl_*
Hope this helps out.