Many sites on the internet will tell you how to control your computer using your iPhone - but what if you want to control your iPhone using your computer? Finally, here's a how-to article for that.
If you haven't jailbroken your phone yet, you're going to need to for this to work. Currently there's no other way to do it. You can find information at the link below - it's easy to do, and completely reversible. Once that's done, open Cydia and install Veency.
Click on the wireless icon in your menu bar at the top of your screen. Select "Create Network." Type in a name - let's say "iPhone" and hit ok. For added security you can also put in a password here.
Go to your iPhone's Settings and select Wi-Fi. Making sure the toggle at the top is set to "On," select the iPhone network from the list. Once it's selected hit the blue arrow to go to the IP information screen. If your iPhone doesn't have any IP information listed, you might need to wait a minute. If you're still not getting anything, head back out to the home screen, open safari, load a webpage, and then come back to the IP information screen in your Settings. Take note of the IP.
Open the VNC software on your computer. I recommend using Chicken of the VNC on a Mac, as it's the only tested setup guaranteed to work. You may have luck with various windows programs as well. Type the IP address from your iPhone into the Host pane and click connect.
If everything went accordingly, your iPhone will now ask you to accept. Click Accept and you're can control your iPhone from your computer!