None.

The purpose of instructional technology is to affect and effect learning with the assistance of hardware and software. Instructional technology is a growing field of study which uses technology as a means to solve educational challenges, both in and out of the classroom. 

Google Inc. has launched a new resource called Google for Educators, which contains classroom activities and teacher guides for using various Google applications to support and enhance the curriculum.    Although the applications offered through the site are free, some may include advertising.  

Visit: http://www.google.com/educators