Remote control of your iPhone might be very useful for testing iPhone friendly web sites. You can use emulators for this purpose. Blackboud iPhone Browser Simulator is not bad, but still this is not a real iPhone browser.
First of all you iPhone needs to be jailbroken. Then you need to install VNC Server for iPhone. Just search for Veency in Cydia, it is free.
On you desktop you need VNC Viewer. There are bunch of them, but I use UltraVNC since it is free. Then you can connect to your iPhone over Wi-Fi, but you can do it thru USB too.
For USB connection you need to install python interpreter and usbmuxd. From usbmuxd we need only python client part. Run connect.bat, which has following line inside:
c:\python26\python.exe tcprelay.py 5900
And then you can connect to your iPhone using 127.0.0.1 address.