These are few theatre research related sites. If there are any more in your knowledge and you think they are useful, please inform us.

AICT
The IATC draws together more than two thousand theatre critics, through some fifty National Sections. Founded in Paris in 1956, the IATC is a non-profit, Non-Governmental Organization benefitting under statute B of UNESCO.

The purpose of the IATC is to bring together theatre critics in order to promote international cooperation. Its principal aims are to foster theatre criticism as a discipline and to contribute to the development of its methodological bases; to protect the ethical and professional interests of theatre critics and to promote the common rights of all its members; and to contribute to reciprocal awareness and understanding between cultures by encouraging international meetings and exchanges in the field of theatre in general.

The IATC holds a world congress every two years, seminars for young critics twice a year, as well as symposiums, and contributes to jurys. English and French are the association's two official languages, and its place of incorporation is Paris.
http://www.aict-iatc.org

All about Jewish Theatre
The Global Website to promote and enhance Jewish Theatre and Performing Arts Worldwide. Director & Chief Editor: Moti Sandak
http://www.jewish-theatre.com

Applied Theatre Guide
A hyperlink resource for those who use theatre techniques for other or more than arts or entertainment purposes, and for those whose theatre styles incorporate other than traditional presentation styles. Categories include Psychodrama, Sociodrama, Theatre in Education etc.
http://www.tonisant.com/aitg/

ASTR
American Society for Theatre Research. A website withy many good links for researchers The American Society for Theatre Research, established in 1956, provides an organization and public voice for theatre scholars and promotes the cause of theatre as a field for serious scholarly study and research.                                                                                                                                     http://www.astr.org/


ATHE
The Association for Theatre in Higher Education is an organization of individuals and institutions that provides vision and leadership for the profession and promotes excellence in theatre education. ATHE actively supports scholarship through teaching, research and practice and serves as a collective voice for its mission through its publications, conferences, advocacy, projects, and through collaborative efforts with other organizations. 
http://www.athe.org

Centre national du theater
http://www.culture.fr/culture/sedocum/cntheatr.htm...

FIRT/IFTR - SIBMAS BULLETIN
http://www.firt-iftr.org/sibmas/site/index.jsp

HAMLET
This site offers anything you want to know about Hamlet
http://lightning.prohosting.com/~shicoff/Lit/hamle...

History of the theater
Oscar G. Brockett on theater history 
http://www.abacon.com/brockett/

ITI
The International Theatre Institute (ITI), an international non-governmental organization (NGO) was founded in Prague in 1948 by UNESCO and the international theatre community. The ITI has national ITI centres in approximately 90 countries. The ITI maintains formal associate relations with UNESCO and is its principal international NGO partner in the field of the performing arts. 
http://www.iti-worldwide.org

LARAS
http://www.ivry.cnrs.fr/artsduspectacle
Le loup theater
http://lelouptheatre.free.fr

Médiéval
http://www.uhb.fr/alc/medieval

OISTAT
The Mission of OISTAT is:

-To stimulate the exchange of ideas and innovations, and to promote international collaboration in professions which support live performance;
-To promote the formation of national centres in each country in order to achieve these aims; 
-To encourage life-long learning among live performance practitioners;
-To respect the integrity of all cultures and celebrate the diversity as well as the similarities of those who work in support of live performance. 

To this end OISTAT has Centres in 38 countries around the world with combined membership of over 12,000 members; six active Commissions undertaking a variety of projects in the areas of Education, Technology, Scenography, History and Theory, Publication and Communication, and Architecture; and a growing active presence on the WWW through its web page.
http://www.oistat.nl

SIBMAS
Since 1954 SIBMAS has been the forum for colleagues from all over the world promoting research, practical and theoretical, in the documentation of the performing arts.

Besides the organisation of biennial international congresses SIBMAS members are involved in three permanent projects. The World Directory on Theatre Museums and Libraries, which was published in its 5th edition in spring 1996, and the International Bibliography of Theatre (IBT), published by the Theatre Research Data Centre at Brooklyn College of the City University of New York. The World Encyclopedia of contemporary Theatre, 5 vol. (1994...)
http://www.theatrelibrary.org/sibmas/sibmas.html

Spectacles du Grand Siècle
http://www.georgetown.edu/spielmann/opsis.htm

The Worlds of Herman Voaden website
The Worlds of Herman Voaden is a website devoted to the experimental Canadian playwright and director Herman Voaden (1903-1991). The site includes all his published and unpublished realist and non-realist "symphonic expressionist" dramas, his theatre essays and critical assessments of his works. The site also features the history of Voaden's collaboration with the noted American Jewish composer Frederick Jacobi (1891-1952) on their opera The Prodigal Son.
http://www.lib.unb.ca/Texts/Theatre/voaden/index.h...

Théâtrales
http://www.er.uqam.ca/nobel/c2545/theatral.html

THEATRON
Theatron Limited is a small, dynamic company specialising in the field of virtual reality and multimedia for cultural heritage clients. We combine the skills of academic and pedagogical specialists, archaeologists, architects, computer programmers, virtual reality modellers and multimedia designers to create accurate, interactive presentations designed to attract, involve, educate and motivate.
http://www.theatron.co.uk

UNIMA 
An international organization aimed at the development of the art of puppetry. ACT - can't find it - there are some 27 million hits on Google under these three letters...
http://www.unima.org

Webthea
http://www.webthea.com