Here are the DVDs which have been released for the orignial movie of High School Musical:

High School Musical
High School Musical: Encore Edition
High School Musical: Remix Edition

       

Here are the DVDs which have been released for the movie of High School Musical 2 and High School Musical - The Concert:

High School Musical 2 - Extended Edition DVD
High School Musical 2 (Blu-ray)
High School Musical - The Concert: Extreme Access Pass