how can it update my iphone 3g? to the new software?,

The iPhone 3G can not be upgraded beyond 4.2.1.

The iPhone 3G can only update to iOS 4.2.1. iOS 6 is not and will never be avaliable to the iPhone 3G. However, if you connect to iTunes on your computer you can upgrade from iOS 4.2 to iOS 4.2.1, but you will never be able to update any higher on your current phone.

You are welcome.

Phillipsteen wrote:

cause i can't get facebook and other things someone help me? 🙂

Although the official Facebook app doesn't work with the iPhone 3G, there are some apps which claim they are compatible. Here are two you can try:

Friends Planet 2

Quickly for Facebook with Video Chat

There are a lot of apps and games which are compatible with your older device. You just need a tool to separate them from the incompatible apps.

Here is my favorite solution:

iOSSearch - search the iTunes store for compatible apps.

And here are some things other people have suggested:

Vintapps 3.1.3 - paid app.

Apple Club - filter apps by iOS version.