IPTV is one of the most highly visible services to emerge as part of the development of next generation network (NGN). IPTV services over manageable broadband link from a provider will be one of the ultimate goals of the broadband revolution using NGN. In this paper, we analyze IPTV architecture developed by ITU-T and provide functional architecture for NGN-based IPTV services according to functional mapping between IPTV and NGN. For this, we provide the detailed functional architecture and relevant operations with other functional blocks and present the harmonized architecture between IPTV and NGN for NGN-based IPTV services with the alignment with existing NGN architecture. As challenging architectural issues, we also introduce personalized IPTV services based on Web-based open platform in NGN environment and illustrate functional architecture and service examples for Web-based personalized IPTV services