1. A method of advertising, the method comprising: determining at least one type of media file format supported by each of a first wireless device and a second wireless device when the first wireless device and the second wireless device enter a coverage area of a wireless data access point; transmitting at least one advertisement for an advertising entity to the first wireless device via the wireless data access point in a first format that complies with the at least one type of media file format supported by the first wireless device; transmitting at least one advertisement for the advertising entity to the second wireless device via the wireless data access point in a different format than the first format, wherein the at least one advertisement sent to the second wireless device is transmitted in the at least one type of media file format supported by the second wireless device; and generating a billing report for the advertising entity based on the first format of the at least one advertisement transmitted to the first wireless device and the different format of the at least one advertisement transmitted to the second wireless device.