Amazon.com
Supplies of most titles and is able to ship books overseas.
Barnes and Noble
Good vendor.

Better World Books
This vendor partners with charitable organizations. A portion of what you pay benifit the partnered organization.

eBook Vendors
List of ebook vendors

Magpies. au
Austrialian published journal. You need to subscribe to the issues, excellent resource for MYP librarians.
Schoolibrariesonline
Intrenational Association of School Librarianship
School Library Association United Kingdom
Published in the UK four times a year. Excellent journal for diverse collection.
Teacher Librarian