Google is debuting a special category for education-related software in its Apps Marketplace, prompted by what it considers the success of its Apps for Education collaboration and communication suite. At launch, the education section of the Apps Marketplace will feature about 20 Web applications, including classroom managers, gradebooks and learning aides. Some of the applications are new to the marketplace, while others were there before. There are about 10 million end users of Google Apps for Education, which is free, and the new Apps Marketplace category is envisioned as a central repository where educational institutions can seek and evaluate applications for students, teachers and staff, said Scott McMullan, Google Apps partner lead, in a phone interview.