The Turkish Culture and Tourism Ministry (www.kulturturizm.gov.tr) has very centralised information, brochures and information on various sights, museums and other attractions in Turkey. However, it is in poor English, even for the most important museums and major attractions and has few helpful images. Municipalities and provincial governorships are much better at providing  regional and local information. It still may not be in excellent English but local, grass roots organisations are doing a better job of promoting themselves than the tourism bureaucrats.  Many hotels and events can be booked on line but not usually from a central portal.