The wide adoption of Web Services and the availability of web APIs are transforming the web into a programmatic environment for developing innovative web applications that combine information from various sources to provide a rich user experience. These mashup applications are characterized by rapid development using existing data sources and the use of new technologies such as AJAX, JSON, etc. Developers often focus on delivering rich functionality via the browser environment and pay little attention to the design and maintainability of the applications. In this paper we describe our experience in developing an Itinerary Planner travel application, and discuss the challenges associated with developing mashups. In the conclusion, we briefly discuss the lessons learned in addressing these challenges and how these lessons can be applied to future mashup projects.