Apple has extended its iAd mobile advertising network to the iPad. Citing an Apple spokesperson, AdAge reports that a spot for Disney’s upcoming film Tron Legacy will be the first iAd to appear on the iPad, and will remain the sole iPad-formatted iAd through the end of the year. According to the report, the iAd includes nearly 10 minutes of video content, images from the movie, a theater locator with showtimes, a preview of the film’s…