The site is reporting that he's co-writing with Mike McCullers, who he collaborated with on Austin Powers: The Spy Who Shagged Me and Austin Powers in Goldmember. Apparently, New Line Cinema is eager for another Powers film as well, although a deal isn't in place as of now.
It is said that this fourth film will focus of Myers' Dr. Evil and the relationship with his son, Scott Evil, which was played by Seth Green in all three films. "It's very personal with a father and son theme loosely based on his own life," an insider told the site.
We'll have more on this new film as soon as more information arrives.