A movie about a dancing teacher who teaches his students

Isn't it "Take The Lead", also known as "Love Dance Teacher and Student".

Title: Take The Lead

Translation: Mainland China Emotional Dance Teacher and Student

Hong Kong and Macau Dance-Excellent

Taiwan Solo Leader

Genre: Music/Drama

Length: 108 mins

Rating: PG-13 (for melodramatic subject matter, foul language and violence)

Production: New Line Cinema, New Line Cinema

Release Date: April 7, 2006 (USA)

Hope this helps :)