The availability of increasing network bandwidth and computing power provides new opportunities for videoconferencing systems over Internet. Multimedia capable devices with broadband Internet connections are spreading rapidly. Even cell phones will have broadband Internet access in the near future. This requires universally accessible and scalable videoconferencing systems that can deliver thousands of concurrent audio and video streams. However, developing videoconferencing systems over Internet is a challenging task, since audio and video communications require high bandwidth and low latency. In addition, the processing of audio and video streams is computing intensive. Therefore, it is particularly difficult to develop scalable systems that support high number of users with various capabilities. Current videoconferencing systems such as IP-Multicast and H.323 can not fully address the problem of scalability and universal accessibility. These systems lack flexible service oriented architecture to support increasingly diverse. We believe that with the advancements in computing power and network bandwidth, more flexible and service oriented systems should be developed. In this paper, we outline a service oriented architecture for videoconferencing, GlobalMMCS, based on a publish/subscribe event brokering network, NaradaBrokering.