Scope of the Implementation Project

What are the scope of work when SAP is implement?
You should have a Project manager from your company, who will work or  should work closely with the implementing Company Project Manager.
The Implementing company will supply the Technical/Functional  Consultants. Your company should provide so-called "Super Users / Key Users. These are persons within the company who know the business and its  processes inside out.
The Key Users will work closely with the Technical Consultants in designing  the companies Business Process to fit with SAP. 
The Technical consultants should pass on their knowledge to the Key  Users. The Key User will train the End Users, so they must be also trained in  SAP Business Process, this is either done by the Implementing company or your company can
send them to SAP training.
The driving person here is your Company Project Manager, in any case all company persons involved in the Implementation project should be on the project 100 percent.
You should setup five phases : 
1.  Preparation 
2.  Blueprinting, 
3.  Realization 
4.  Preparation Go Live 
5.  Go Live/Support
From the Project Management side, there are many thing that must be set up prior to Blueprinting, such as Project Charter, Project Plan, Risk Management  Plan, Change Management plan etc.
As far as a SOW, this is part of your Charter and there are many Templates of such documents, you need more than just the template, you must know how to analysis your overall environment (Company goals, landscape, Business objectives  etc) 
in coming up with the Scope. More than one person is involved in the SOW defination.                       *-- Ricklay