Anabelian geometry study materials?

There is this very beautiful survey

Nakamura, Hiroaki; Tamagawa, Akio; Mochizuki, Shinichi

The Grothendieck conjecture on the fundamental groups of algebraic curves

http://www.math.sci.osaka-u.ac.jp/~nakamura/zoo/rhino/NTM300.pdf

You could also have a look at

Szamuely, Tamás

Heidelberg Lectures on Fundamental Groups

http://www.renyi.hu/~szamuely/heid.pdf

Jakob Stix, Rational Points and Arithmetic of Fundamental Groups Evidence for the Section Conjecture Springer Lecture Notes in Mathematics 2054, xx+pp.247, Springer 2012. http://www.springer.com/mathematics/algebra/book/978-3-642-30673-0

This volume, Galois Groups and Fundamental Groups, edited by Leila Schneps has a great collection of articles, as does this volume, Geometric Galois Actions, including a nice article by Florian Pop on "Glimpses of Grothendieck's anabelian geometry."

If you'd like videos, here is a series of lectures on related topics, including a long series by Pop on anabelian geometry. At MSRI, you can find some lectures from Fall 1999, including one specifically about anabelian geometry.