A great feature of Mac OS X is the ease of sharing your Internet connection. For example, you are in a hotel with your family or coworkers, you have wired or cellular Internet access (this includes EVDO cards, USB cell cards, etc.), but more than one of you needs to be connected at the same time. With your MacBook, MacBook Pro, or MacBook Air (with optional USB-Network connector), you can share your connection safely and securely!
MacBook Internet Connection Sharing — Office Cafe