ebooks are listed in Omni and here are a few useful collections:
O'Reilly for Higher Education
Technology and business ebooks from more than 250 publishers, along with videos, case studies, learning paths and self-assessments. Includes Harvard Business Review 'must reads' audiobooks.
ProQuest eBook Central
A large multidisciplinary collection of ebooks from a variety of publishers.
Skillsoft - ITPro Collection
business, technical and engineering content containing thousands of digitized "best in class" books, book summaries, research reports and best practices.
Scholars Portal Books
Multi subject collection of e-books from academic publishers (such as Springer, Oxford University Press, Cambridge University Press, and Elsevier), Canadian publishers, government and non-governmental organizations.
For more on finding ebooks, click here.