Mashup is a new web 2.0 technology for data aggregation applications, combining data from different sources to create valuable information. The uses of mashups are often more data related than process related. In this paper, we explore the differences between data-oriented mashups and process-oriented enterprise mashups and consider how process mashups can be used for virtual enterprise collaboration. We highlight the modeling of end users' process mashup applications from both a control flow and a data flow perspective. Based on our analyses, a lightweight process modeling approach is proposed for process enterprise mashup applications. Our approach, illustrated by reference to an example personal collaborative activity, will support collaboration among users with different levels of modeling skills and expertise in a virtual enterprise environment.