The Austrian Federal Ministry of Education, Science and Research is the federal government agency responsible for higher education in Austria. This website serves as a good starting point if you are looking for in-depth information (e.g. full texts of federal laws establishing university programs).
The Austrian Exchange Service - Österreichischer Austauschdienst (OeAD) is the Austrian agency for international mobility and cooperation in education, science and research and a major clearinghouse for study-abroad information in Austria, both for incoming and outgoing students.
"Uni-Wegweiser" (Study Guide) another guide to Austrian universities, again in English; links to fields of study and respective curricula.
Austrian institutions of post-secondary education: A list of post-secondary institutions compiled by Margit Geyer (National Agency Lifelong Learning Austria, OeAD) and Heinz Kasparovsky (Austrian Federal Ministry of Education, Science and Research, ENIC NARIC Austria). The brochure (66 pp.), published in May 2010, is also available for download at the OeAD website.