Until last week when the iPhone 4 was finally jailbroken, your only option to tether the iPhone 4 was to go through the official, legit and expensive way: AT&T. If like me you think that an extra $20/month just to tether your iPhone 4 is a little too much, we've got a solution for you. It's called MyWi.
We've talked greatly about MyWi on iDB before but for those of you who just arrived let me tell you briefly what it does. MyWi is an app that let's you turn your iPhone into a wifi hostpot. Turn it on and share your iPhone Internet connection with computers around you. That's how simple it is.
Tethering Your iPhone 4 Using MyWi
Step 1: Make sure your iPhone 4 is jailbroken (see iPhone 4 jailbreak instructions)
Step 2: Launch Cydia and search for “MyWi 4.0”.
Step 3: Download and install the free MyWi trial then reboot your iPhone.
Step 4: Launch MyWi and tweak the settings to your liking:
Change the hotspot name
Change the channel
Enable Wep security
Enable USB/Bluetooth tethering
That's it. You can now tether your iPhone using MyWi. Your iPhone doesn't even have to be plugged in your computer. You can just use MyWi as a hotspot, but remember it will drain your battery like crazy.
While MyWi is not illegal in itself, AT&T (or your local carrier) might have a policy in place to prevent you from using apps like MyWi. As long as you don't get caught, it's all good...
If you want to keep MyWi after the 10-day trial, it will cost you about $20. Although it comes with a hefty price, I believe MyWi is one the best jailbreak apps out there.
UPDATE: There are cheaper alternatives to MyWi. Click here for more info.