I am currently buying an Ibook G4, but i don’t know how I can get internet on it. What is the best servicce i could use to get internet on my ibook. I could use WI-FI but i need a service that can give me internet anywhere outside home. What is the best service i can get and how do i get it?

You do know that an iBook G4 is at last 5 years old? It should have an Airport card in it for you regular wireless, most likely it is a "b" type wireless card, at best you can put a "g" in it. You can check eBay for used ones if yours doesn’t have one it it. If you have a wireless router in your home, you can use it there. You could also use it at places like libraries, motels, coffee shops, McDonalds etc. If you want to use it "on the road" you will need a cell phone wireless usb adaptor. It plugs into one of the USB ports on the Ibook. Places like AT& T and Verizon will give you one free but you have to sign up for a 2 year service package at about $40 a month.
If you want to get a couple more years service on the iBook, upgrade the system software to MacOS X 10.4 (Tiger) and make sure you have at least 1 gb of ram. It may take Tiger to get a cell phone usb adaptor to work. You’ll probably also need a new battery, skip eBay, most batteries there are knockoffs and can damage your Mac.