If I had to describe to a fellow teacher what TPACK is all about, I would actually refer them to the following video:
The author of the video, Royce Kimmons, gives a great, brief explanation of TPACK. In my own words, I would describe TPACK as taking the knowledge we have as educators in our content area, pedagogy, and technology and combining them to provide our students effective and beneficial lessons in our classrooms.
Punya Mishra's keynote speech from the 21st Century Learning Conference - Hong Kong 2012, provides a great explanation of the importance of TPACK not just for educators, but also for students.
Punya Mishra and his colleague, Matthew J. Koehler, explains that teachers' understanding of content, pedagogy, and technology, can be integrated with one another so that both the teachers' and the students' knowledge can improve.
Mishra and Koehler have written numerous articles pertaining to TPACK. They have sited teachers that have used the TPACK process and have truly made their classrooms ones where content, pedagogy, and technology have worked together to present meaningful information. The following is a link to an additional article writtnen by Mishra, Koehler, and other that I found helpful: TPACK - Development and Assessment Preservice Teachers.
In short, TPACK is taking what we as educators do in the classroom to the next level. We utilize technology that is available to us to present our students with content in an effective manner. By doing so, we not only enhance the learning experience of our students, but we also become better educators and students ourselves. It allows the students to experience information in a multitude of ways and from multiple sources. The learning does not stop when they leave the classrooms, rather we give them the ability to continue learning on their own with the use of technology.
It is a great time to be a student, but it is even a greater time to be an educator!