This paper explores the issues and the techniques of enabling multimedia applications for the thin client computing. Our study on the network applications over thin clients is devoted to the universal plug-in architecture which supports multimedia applications over thin clients. With the proposed architecture, the universal plug-in technique is devised to shift jobs from thin clients to a supporting server, thus reducing the computing overhead required by the thin clients. In addition, this plug-in architecture is implemented and empirically evaluated. It is shown by our experiments that the proposed architecture not only significantly enhances the multimedia capability of thin clients but also reduces the memory consumed by the clients for various applications, showing the very advantage of the universal plug-in architecture for thin clients of limited resources.