Traditional concept of services focus on Web based information centric services. In this paper, we study virtual services which mean services over 3D Internet/virtual worlds. We focus on studying the learning applications as one type of killer applications of virtual services. We show that virtual learning services have rich opportunities of service innovation. Virtual services have additional dimensions beyond traditional Web services which have significant influence on both its research and industry applications. We not only give the problems of learning design in 3D virtual worlds, but also summarize patterns for virtual learning solutions and architecture of virtual learning. With several case studies, we show the applicability of those key concepts and methods in the design and development of virtual learning services