The Little Mermaid: Ariel's Beginning (DVD 2008)

From the Disney site:
Every story has a beginning but only one begins under the sea
...Now, for the first time ever, discover the story you never knew in ''The Little Mermaid: Ariel's Beginning,'' an all-new motion picture only on Disney DVD. Returning favorites Sebastian and Flounder join Ariel, her six sisters,
and the deliciously wicked new villain Marina Del Rey in this all-new movie filled with spectacular animation in the tradition of the original, and overflowing with new songs from award-winning composer Jeanine Tesori. Long ago, in a kingdom where music is outlawed, King Triton's youngest daughter, Ariel, discovers her love for music in a secret, underground music club. Torn with the choice of whether to hide her passion or share it with her father and risk losing everything, Ariel sets off on a daring adventure to restore music to Atlantica. Rated: Anticipated G . Available to own August 26, 2008
You can order The Little Mermaid: Ariel's Beginning from Amazon and it will be delivered to you. How convenient is that?  Or find Ariel's Beginning DVD on our DVD page.
I've seen the movie and it is definitely worth having.  The animation is true to the original, and Jodie Benson is Ariel's voice (again) so there is wonderful continuity between the movies.
Look for the Hidden Mickey in the movie!  (Hint:  the octopus has something to do with it)