Mobile Cloud Computing refers to an infrastructure where both storage of data and processing of data happens outside of the mobile device. In short, mobile applications move the computation power and storage from the mobile phones to the cloud. This will be huge save to the computation power of the mobile and it will increase the speed of the applications.
Some of the examples of Mobile Cloud Computing applications are Gmail, Google Maps and various other applications. As of now, most of the applications uses mobile devices for its computation. But, in future all the data storage and data processing will happen in the cloud.
The Below presentation will give you some good overview of the Mobile Cloud Computing.