With the rapid development of web services technology, the Internet becomes a giant programming interface and users can access and use the information via such an interface [1]. And the need on facilities for end users to achieve web task automation becomes more significant as the number of web services and online users increases. In this paper, we describe the proposed architecture of such an end-user builder called WTABuilder in a web services setting. WTABuilder makes use of the existing Web Service Oriented Architecture as the infrastructure [2]. Our WTABuilder architecture is designed for endusers to build complex web service-based tasks and to perform the tasks automatically. This paper gives a description of the infrastructure in place and briefly explains each component involved. The preliminary design of major components in the proposed architecture is presented.