This book details the design and implementation of Short Messaging Service (SMS) and MMS applications. The main aim of this book is to provide SMS/MMS developers with the tools necessary to develop applications which can send SMS/MMS messages to groups of mobile devices. 1. The first section of this book presents a Java SMS application which allows the storage of contacts and groups of contacts. Thus the user of the application can customise his/her own list of contact 'Individuals' and 'Groups' of contacts (Such as: 'Family', 'Friends', 'Work Colleagues' etc). Upon selection of Individual(s) and/or Group(s) a single message such as "how r u all" can be sent to all their respective Mobile Stations (MS) by clicking on the 'Add' and then 'Send' button. The simplicity and ease of use of this application allows a diverse range of users from an individual home user to corporate wide user base. All code is presented and a working version is freely available for download.2. The middle section of this book presents a similar group bulk SMS application which is web enabled. The application is written using Active Server Pages and is purely web based. Again, it allows the sending of messages to individuals and groups. For the purpose of sending SMS in each scenario, the Simplewire Active X Software Development Kit is used. All code is presented and a working version is freely available for download.3. In order for "rich media" MMS messages to be sent and received, they must first be transcoded into the MMS format. Essentially what happens is that the content is tailored before it arrives at the mobile. This tailoring process is called transcoding. Transcoding systems can adapt video, images, audio and text to the individual constraints of different devices. They summarise, translate and convert the content into the MMS format. This section of the book presents a transcoding framework, which enables various rich media files stored on PC to be sent to MMS capable handsets. Transcoding is the area that this project will focus on. A java application is developed that allows a user to select multimedia content stored on the computer and send it to a mobile. The application performs the transcoding of the message content into MMS format and deploys the message to the mobile.