How does united mileage plus work?

United mileage plus is the name of United Airlines' frequent flyer program. Membership to this program is free and can easily be acquired online. Once you become a member, mileage is credited to your account for any flight you sign up for - these flights must have been on United or its partners. You can also earn mileage through the United Plus Visa credit card, staying at certain hotels, using certain car rental agencies or cell phone services. Remember you only begin racking up mileage after you sign up for membership.