Full wireless connectivity, that is, you have a wireless adapter on your computer and receive a wireless signal from 'somewhere' without benefit of a wired connection to your house, is VERY rare. Some cellular phone companies do have this type of connection. One purchases a wireless PC card, just like one does a cell phone, and use the card to connect to the cellular broadband system. The fee for this type of service is not inexpensive in the US.
The systems that broadcast a wireless signal that can be picked up by a normal PC-Card, exclusive of cell phone systems, is called WiMAX, and is under development, probably at least three to five years in the future for general access.