In this tutorial, we learn how to tether an iPhone 3G or 3GS. First, go to Cydia, then manage, then sources, and add "sinful iphone repo" to your phone. Now, click into the source and find the text that says "enable tethering" and choose which phone you have. After this, you will see that the tethering is installed, then continue and confirm. Then, go to settings, general, network, and it should say "internet tethering" towards the bottom of the screen. From here, you can restart your phone and then it will be tethered so you can use it elsewhere whenever you need Internet!