"It's all happened quite suddenly but I'm looking forward to coming back," he told the clubs official website.
"The chairman approached me a couple of weeks ago and I soon realised how much I missed my old job and it's one which I very much enjoy.
"That's where I feel my strengths lie. When I was promoted to caretaker manager the first time, I said that I didn't want it full-time.
"Then, when Paul Sturrock went, I was asked to become head coach and accepted. But having gone through that process, I decided my future was in youth football."