Using your iPhone 4 with ioS 4.3 it is possible to share your iPhone data connection with other devices wirelessly, such as a laptop or an iPad. A few things to note on this, if you have an iPhone 3GS you can still do this but only via USB or Bluetooth, also you cannot share your wifi connection, only your cellular data connection, so make sure your data network has you set up on an appropriate plan for this, some providers include this data plan automatically some do not. Check first.
It’s actually not difficult to use. Under settings click on Personal Hotspot. It will be set to off, click to enable it. If you are currently connected to a wifi network, it will be disabled while you have personal Hotspot enabled – you can only share a data connection, ideally would need to be 3G and not EDGE.
Next, you will be asked if you want to enable the connection via wifi and bluetooth, or just via USB.
Once you enable the service, you can set up a password, but you cannot disable it. Now up to five devices can use the data connection on your iPhone!