You may also want to read Evaluating Tools: A Five-step Process for Comparing, Evaluating, and Choosing the Right Tool Also, a step-by-step process for evaluating test tools, running a pilot for the tested tool, implementing it across the organization, and making good use of it now you've got it, is found in Software Test Automation: Effective use of test execution tools (Mark Fewster and Dorothy Graham: ISBN-10: 0201331403; ISBN-13: 978-0201331400).
Walter