So if I buy a card, I can access WiFi with my iBook? Like at Panera Bread? (Coffee shop that advertises free wifi.)
Cards are a bit pricy - on the line of $50 dollars. If you do buy one, get a B/G card - that's pretty much all they sell. And make sure it's compatible with your iBook. Go to best buy and tell the geek what computer you have. I don't know Macs at all so I can't tell you if your iBook will cooperate.
But yes, once you have a card, you can get wireless internet anywhere that offers it. Some places don't offer it free. I think Borders uses T-Mobile and you have to pay, but Barnes and Nobles usually just has free internet... lots of coffee shops have free internet... heck, there's a McDonalds here that has free wireless.