Firstly, before anything else, make sure that the battery of the iPhone is fully charged, and also if you are using a laptop, make sure it is plugged into the power outlet.
If you must use the battery on your laptop, make sure you have enough power to last through downloading a 200MB file, installing, and updating your phone. You don't want your laptop to die in the middle of your iPhone update â€“ who knows what will happen.
Secondly, end users need to download and install iTunes 8 . iTunes 8 lets the phone communicates with the computer so it can be updated.
Next prepare to connect the iPhone to the computer with iTunes 8 software installed. Wait for sometimes until iTunes opens. When iTunes opens, select your iPhone under Devices in the Source List on the left and then navigate to 'iPhone Summary pane' and click the buttons for 'Check Update'.
In no time a message will appear click 'Download and Install' wait until the updates has finished and there you have it the new iPhone OS 3.0 software updates.