My definition of the field of Instructional Design and Technology is, the process of using theory based knowledge about learning and teaching in conjunction with technology to increase the skills and knowledge of learners and improve performance.
Some interesting websites about IDT include:
Instructional Design – This site includes a information about learning and teaching theory and instructional design models – a very informative site. http://instructionaldesign.org/
Jeannette Campos – Building a Learning Centered Classroom – An ISD designer talks about her goals and processes – http://www.astd.org/Publications/Blogs/L-and-D-Blog/2014/08/Building-a-Learner-Centered-Classroom?mktcops=c.learning-and-development&mktcois=c.instructional-design~c.eval-learning-impact~c.engagement-motivation~c.training-delivery