The Google apps market is THE place to visit when you are looking for free web applications. The purpose of this website is to help business-like schools run more effectively and in the case of education provide us with tools to challenge the way students learn.
If schools run their business through Google Apps the idea is that by simple clicking a few buttons you enable web based applications across schools if you wanted to.
While Google Apps is focused on helping business run their business on the web more efficiently they have recently released an Education category for schools. Schools can now more easily access apps that help their students and classes learn more effectively.
Google Place Market Place - Become an App Ninja