All presented internet portals offer comprehensive information on art, but have different focuses which are alluded to in the comment.
is a portal encompassing i.a. museums, publishing houses, foundations, and the latest news on art in Germany (in German).
www.art-in.de/index.php
compiled by the Goethe-Institut in Paris, offers links to visual and fine arts in Germany and German visual and fine arts in France (website in German and French).
www.goethe.de/ins/fr/par/kue/deindex.htm
is a very well organised portal on art and art history by Helsinki's University of Art and Design (arranged according to themes).
www2.uiah.fi/internetguide/navigator.html
Incredibly huge collection of links concerning film worldwide (!) by Bibliotheksservice-Zentrum Baden/Württemberg (BSZ).
titan.bsz-bw.de/cms/recherche/links/fabio/fabioFILM.html?set_language=en&cl=en
is an international database on contemporary artists (not limited to the visual arts!) containing extensive biographies.
www.culturebase.net
Goethe Institute's portal on current festivals and trends, introductions and detailed background reports, portraits of leading choreographers, a comprehensive list of addresses of choreographers, promoters and institutions and further links to other relevant sites.
www.goethe.de/kue/tut/enindex.htm
The German-Chinese Culture Network ("Deutsch-Chinesisches Kulturnetz", "中德文化网") provides a platform for the cultural exchange and dialogue between China and Germany.
www.de-cn.net (website in German and Chinese)
The International Federation of Arts Councils and Culture Agencies (IFACCA) is the first global network of national arts funding bodies.
Literaturportal.de presents lists of the literary events happening in all 16 states, profiles of every major German author, sound bites of major authors reading their texts, and information on the libraries, archives, literary houses, and museums that host author events (in German).
The German Music Information Centre provides information on all aspects of musical life in Germany, e.g. music education, amateur music making, music promotion and funding, orchestras, music theatres and festivals, research and documentation, music in the media and music economy. The Centre cooperates with information centres and music institutions on the local, state and federal level in order to develop and maintain its services. It publishes databases on music life in Germany with articles, music-statistical data, cultural-political documents, surveys and information on the infrastructure of musical life (website currently only available in German).
lists the most important exhibitions worldwide, and amongst other things, organisations for art and culture, all sorts of places where art-exhibitions take place, media (i.a. bookshops, culture pages in the newspapers, radio stations...Website in German)
kunstaspekte.de/index.php?action=termine
offers links to all branches of art, including stage, film, music... By Schroeter Design, Düsseldorf (website in German)
www.kunstfinder.de/index.htm
a portal for the worldwide promotion of contemporary German literature.
This project initiated by the Federal Cultural Foundation, Germany, in cooperation with the Goethe Institute and the Frankfurt Book Fair provides information on an ongoing basis about the most important new publications in the fields of fiction, non-fiction and children’s and young people’s literature through presenting excerpts and specimen translations, as well as in-depth book reviews.
www.litrix.de
is a non commercial information system on the visual arts of Africa, Latin America, Asia and the Caribbean within the context of international art processes (website in English and Spanish!). It provides amongst others systematic collections of commented links on the art of particular countries of these regions.
universes-in-universe.de/english.htm
informs about www exhibitions, internet porjects and the art scene.
www.goethe.de/uun/prj/pru/enindex.htm
by the "Centre for Cultural Policiy Studies", Warwick University with links to art centres, cultural management, dance, film and tv, music, publishing, and theatre in England. Links to cultural policy concerning the whole of Europe.
www2.warwick.ac.uk/fac/arts/theatre_s/cp/
(German Film Institute)
One of the largest film archives concerning all aspects of cinema and film in Germany:
www.deutsches-filminstitut.de/dframe12.htm (website in German).
A compilation of all museums in Germany providing notes on current exhibitions and events, general information about particular museums as well as some useful tips concerning your visit.
Deutsches Museumsverzeichnis (website in German).
is a tool to connect databases containing material on contemporary art all over Europe. It provides information on artists, their activities, presentations in museums or galleries as well as photos and texts.
ean.dark-star.ch/
This internet platform is an entrance for media art and provides a publicly accessible online-archive with multimedia presentations of works and projects as soon as numerous video documentations of lectures by prominent artists and scholars.
netzspannung.org/index_flash.html