You can find release dates for Hindi movies on BollywoodHungama.com. The site's Movies section has information about recently released and upcoming Hindi movies, with release dates as well as news about the movies.
Hindi movies are commonly known as Bollywood movies. The Bollywood industry is the largest film industry in India and one of the biggest in the world. The word "Bollywood" is a portmanteau of Bombay, the former name for Mumbai (where the industry is based), and Hollywood.
Bollywood Hungama was launched in 1998 and is a leading resource for news and updates about Hindi movies. The site was formerly known as indiaFM and is available in English.