I've added this to the Scooby Doo page, but a third "Scooby-Doo" movie has begun production in Vancouver, but will bypass theaters and feature a cast of unknown actors. "Scooby-Doo: In the Beginning," a live-action/computer-animated film, will debut on Cartoon Network in fall 2009 when it also will be released on DVD. As a prequel to the 2002 and 2004 "Scooby-Doo" movies, it finds the Mystery gang uniting for the first time to solve the haunting of their high school. The original quartet of Freddie Prinze Jr., Sarah Michelle Gellar, Matthew Lillard and Linda Cardellini has been replaced, respectively, by Rob Amell ("Life With Derek") as Freddy, newcomers Kaitlyn Melton as Daphne, Nick Palatas as Shaggy and Hayley Alcroft as Velma. The computer-generated Scooby-Doo will be voiced by Frank Welker, a longtime voice actor on the animated "Scooby-Doo" series. Brian Levant ("Are We There Yet?") will direct the movie.
Pretty nifty, huh? The source is here.