The mobile phone has become one of the most popular products amongst today’s consumers. Mobile applications or mobile apps are applications developed for small handheld devices, such as mobile phones, Smartphones, PDAs and so on. Mobile apps can come preloaded on the handheld device as well as can be downloaded by users from app stores or the Internet. In this provides an overview of important mobile application issues in various mobile platforms and research issues related to the development of applications that run on mobile devices.