Kjell Samuelsson, who took over as Phantoms head coach early last season, will become Berube's assistant again and be responsible for the team's defensemen.
A new addition to the mix will be former Phantoms goalie Neil Little, who will be the new goalie coach.
"I'm really excited about this," Flyers general manager Paul Holmgren said. "I think it's going to be tremendous. It's really a nice fit for both teams."
Mullen was hired to be the franchise's assistant AHL head coach when Berube was tapped to help Flyers coach John Stevens after the Ken Hitchcock firing. Mullen is the first American-born player to score 500 goals and 1,000 points in the NHL.
Holmgren said Mullen would work with the team's younger players, developing skills.
"He's another guy with experience that will bring some new ideas to the offensive side of the game," Holmgren said.
Assistant coach Terry Murray will remain on the Flyers' bench. He worked with the team's defense last year but was also in charge of special teams.
McIhargey, who played for the Flyers from 1974-77 and again from 1979-81, will join the club to work with the defensemen.
"He's got lots of experience and I think he's got good energy, he's a good one-on-one teacher," Holmgren said. "He'll bring a real enthusiasm to the bench and to practices." *