The first few chapters of Dark Side of the Moon have been submitted: http://www.twilighted.net/viewstory.php?sid=13459
You can call it Alternative Universe, derived from canon because it takes place in the future after Breaking Dawn, when Renesmee is nearly fully grown. This story has original characters added, and though it sticks to the basic canon, the added characters add their POV over the events of the story.
In short as far as the basics of the story, Nessie has a friend unexpectedly visit her in Forks. The Volturi, weakened after the confrontation in Breaking Dawn, try to save face by allowing vampires, shape-shifters and hybrids to intregrate themselves into mainstream society. The motives behind this aren't fully known, just as it's not fully known why Nessie's friend has moved to Forks. In the end, this friend goes down a path of destruction, and Nessie and her family must try and stop him.
Rated PG-13 for mild language, some sensuality, and themes concerning teenagers/young adults.
Audi, Twilight, Cher, Pink Floyd, symphonic/progressive rock, KStew, RP, Bio-Booster Armor Guyver-what's not to like
Team Renesmee, Team Bella, Team Edward.
Fan fic stories: http://www.fanfiction.net/u/2192109/