The leader of today's mobile development community is Java. The introduction of the Java Micro Edition allowed for the development of rich content for cell phone devices.
On my cell phone I have a number of games, some simple applications, and a news reader, all of which have been written for mobile devices.
Did I mention that my cell phone is a little older than most and has less than a 1 MB of storage? This means that using Java programs is not only efficient, but they have the benefit of being tiny, too. When you are dealing with mobile applications that can only use G3 networks to pass data then "small" had better be your daily mantra. G3 is the international standard for wireless networks. Countries such as South Korea, Japan and the Netherlands have had full scale G3 networks in operation for several years. With a G3 foundation network, you are guaranteed a data rate similar to DSL. This means you can bring broad band technologies to your cell phone over a wireless network.