This paper discusses the role of customized learning environments in the teaching of English to undergraduate science and technology students and focuses on a more subject-specific and skills-oriented approach in English for Specific Purposes (ESP). It may be argued that multimedia technology and the Web have a vital role to play in integrating often complex subject matter and language learning. As most university level students nowadays are mostly conversant with multimedia and Computer Assisted Language Learning (CALL) packages and feel at home before a web-based interface, creating teaching materials to cater to their needs requires a whole new set of skills, not least a knowledge of Web-design and Web-authoring programmes. Educators now need to create environments in which students can learn; they engineer new situations. Let us call it "WELL by design". The focus is on motivating learning, a move towards constructing knowledge and involving the students in meaningful interactions. This paper focuses on how web-based materials are incorporated in day-to-day classroom teaching, how students are encouraged to interact with these materials, and how interaction is promoted and encouraged through the creation of pair and group activities based on the materials. Particular attention will be given to the potential of Web Enhanced Language Learning (WELL) in encouraging collaborative and constructive learning processes. The relationship between tutor and learner in a technology-enhanced environment will also be considered and discussed. A demonstration of specially devised link-mediated learning units within a web-enhanced course in ESP designed specifically for environmental science students will be made, together with an overview of resources, tools and observations within the context of the technology classroom. Particular emphasis will be placed on CALL and WELL as an essential support within a fully integrated language course for science students, as well as on the community-creating and connecting spirit of the Web in a virtual language learning environment.