Just as with print resources, as the number of Web-based resources continues to soar, the need to evaluate them has become a critical information skill for both children and adults. This is particularly true for schools where librarians often are called on to recommend Web resources to classroom teachers, parents, and students, and to support students who must select and use appropriate Web resources for homework assignments and classroom activities. Because of the dynamic, interactive nature of Web-based resources, new tools are required that encompass a broader concept of evaluation, beyond assessing authority and accuracy of content, soundness of functionality (Alexander and Tate 1998; Nielsen 1994), and value-added information design characteristics, such as currency and coverage (Taylor 1986). Tools used to evaluate the Web today also must be able to assess the website's ability to engage and satisfy, or what the authors (2000) call its "motivational quality." Motivation explains why people choose certain activities over others. One of the most widely researched and applied motivation theories, Expectancy-Value (E-V) Theory (Fishbein 1963), specifies that a person's motivation depends on his or her perceived value of and expectation for success at a given task. In this article the authors explain how they used E-V Theory to describe characteristics of websites that might stimulate a person's motivation to visit, explore, and revisit websites (Small and Arnone 1999) and went on to develop a set of unique instruments, based on E-V Theory, originally called WebMAC (Website Motivational Analysis Checklist). Herein they describe why WebMAC was innovative, why it wasn't adequate, and how WebCHECK: The Website Evaluation Instrument (a.k.a. WebCHECK) was developed. The revised evaluation system includes four new updated instruments: (1) WebCHECK Junior for lower elementary students (sixteen items); (2) WebCHECK Middle for upper elementary/middle school students (twenty-four items); (3) WebCHECK Senior for high school students (thirty-two items); and WebCHECK Professional for educators (forty-eight items). The authors discuss how WebCHECK addresses WebMAC's shortcomings, how WebCHECK's scoring system works, pilot testing that was conducted, and what can be found on the WebCHECK website.