Video-on-Demand (VoD) services using peer-to-peer (P2P) technologies benefit by balancing load among clients and maximizing their bandwidth utilization to reduce the burden on central video servers with the single point of failure. Conventional P2P techniques for realizing VoD services only consider data between active peers in the same VoD session. They never consider those inactive peers that have left the session but may still hold partial media content in their local storage. In this article, we propose a novel architecture to construct a fully decentralized P2P overlay network for VoD streaming services based on a multioverlay concept. The architecture is referred to as MegaDrop. It not only takes the types of peers into consideration but also provides mechanisms for discovering nodes that may contain desired media objects. Such a P2P-based scheme can distribute media among peers, allow peers to search for a specific media object over the entire network efficiently, and stream the media object from a group of the peers. We employ a layered architecture consisting of four major tiers: Peer Discovery Layer, Content Lookup Layer, Media Streaming Layer, and Playback Control Layer. The evaluation results show that our architecture is particularly efficient for huge media delivery and multiuser streaming sessions.