I recently bought a nokia 770 internet tablet, it says that I access the internet through wifi or cellphone. Can someone give me the information on wifi? What is it? How do you use/activate it and are there any fees? Do I need services like an internet provider with monthly fees? Are there any other things that I may need to purchase?

What are some interesting/creative ways wireless technologies like ZigBee, Bluetooth, WiMax, WiFi, GSM are used in the world?