Project Planning is the reponsibility of Project Manager 
and generally they user MSproject plan.

Once requirement is gathered next phase of SDLC is projct 
planning.Planning phase involves optimum utilisation of 
resourses, budget, team members and team size. 

Planning document consists of project ID, project name, 
project description,start date, end date, project manger 
name and team lead name, team size etc.