Recent developments of Google Map, Yahoo! Map and MapQuest APIs have pushed map mashups almost to the top among other types of mashups such as news mashpups, search and shopping mashups, and video and photo mashups. However, map.mashups should not reply on these open data sources and services only. Developing a mashup in general, implies a number of challenges. This thesis first evaluates existing mashup technologies, such as Google Map, Yahoo! Map, and AOL (MapQuest) in the context of map mashups. The results are then used in creating two map mashups for the two selected case studies related to participatory GIS for e-government services. Several commonly used APIs have been selected and integrated into the prototype mashups to support municipal planning and West Nile reporting services, to assess the potential issues concerning data and technology integration for online participatory GIS. The results demonstrate that map mashup has great potential to improve and facilitate the rapid development of the future participatory GIS and e-government services. However the existing mashup technologies may not provide techniques or designs satisfying some special e-government requirements.