well, in the sonic movie, metal sonic saves the president's life, but then falls into a volcano. Sonic tries to save him, but metal sonic refuses saying: "There is only one Sonic." So sonic didn't kill metal sonic, but metal sonic sacrificed himself.
No new Sonic movie has been announced. Wroung it comes out July 4th 2011. You can check websites for the movie, Jaleel white voices Sonic in it. Check this website and you'll see. sonicfanfilm.com/blog/?more=31