How to use 3g on the iPhone 4?

I have the 3g iPhone 4 but when i go out and try to use the internet it doesn't work?

Make sure that it is on
Go to Settings --> General --> Cellular and see if it is on
Thats the best I can help you
If that doesn't work then you will have to see your cell phone provider for further assistance

Put 3G on in mobile data In general settings and wave your phone around till it says 3G at the top

You have to go into settings and make sure that "enable 3G" is turned on. Also make sure you that using the internet without Wi-Fi is included in your plan because if not, then your phone bill will be HUGE!