When I bought my iPad, I bought the version with the 3G connection. The idea was that I could then use my iPad on the road. As soon as I showed my new iPad to my friend Andrew, he showed me how to connect my iPad to my iPhone, and use the iPhone to go online.
I didn't realise that the iPhone allows you to set up a personal hotspot, and then connect other devices to it. The iPhone uses bluetooth to connect to these devices, so you have to pair the devices together.
I have since found out that you can do the same thing with an android phone.
However, you loose true GPS if you do not have 3G/4G.