The sites collected here are specifically for mobile platforms. Most are not FREE but offer good value and are suited for iPhones, PSPs and other mobile or smartphone-like devices.
Classic mobile porn is that which can be made portable and taken with you, like downloadable adult movies or short clips of porn movies.
Classic phone porn services are those which require an internet connection, like streaming video or video on demand, and usually work best on devices with 3G or WiFi.