Today, mobility has become the key component of modern live, strongly driven by mobile connectivity via satellite communication, wireless networks, interactivity and mobile user devices. This huge networking potential offers the ground for numerous applications in almost every societal domain. Due to the novelty of most of these products and services, many of the current applications are yet experimental and exploratory in nature, and subject to permanent evaluation and improvement. As new devices, applications and services emerge, also the number of mobile users is increasing in a rapid manner. Mobile broadband networks like UMTS, EDGE or Wireless LAN make it possible to reach a critical mass of users who gain access with their personal mobile devices, equipped with multimedia and data capabilities. Due to this development, new interesting possibilities arise for many areas. One of these areas is the tourism sector, which is being referred to in this thesis. The broad range of the field calls for explicit design guidelines, providing the highest simplicity and ease of use to the future customer. Companies are offering tailored products filling the needs of their customers. Personalization becomes a popular trend in this sector. With the recent hype of so-called location based services, the consumer keeps calling for more usable products, featuring more intuitive interfaces. Others may fear being overwhelmed with features. Especially for the senior users, a relatively big target group for most mobile applications, these products often remain a miracle. As a sustained level of user satisfaction is critical for the outcome of new services and products, this study will evaluate existing applications, provide insight information into usability and demonstrate design evaluation strategies to successfully develop interactive mobile services.