This video tutorial is going to show you how to use Skype over the 3G network on your iPhone. For this purpose you will need a jailbroken iPhone. Go to Cydia and launch it. This will take a bit of time. Make sure you have the latest Mobile Substrate & Skype. If not, follow the video and download and install it. Then press home button and come back to springboard and click on Skype. It takes sometime to load. Press on the free phone and press call. If you want you can select speaker and there are other functions like hold, mute and end call.