Your profile says you are a Systems Consultant. That means, you should have some kinda experience.
Tell me honestly, did you try to search for it before throwing your quention to us here in QAForums? I put "skill matrix" in google and the first URL gave me a good reply on what skill matrix is. First line of that site says,"The skills matrix indicates the level of skills within the team."
You will have to understand that qaforums is not google or wikipedia. It is a Forum and a 'Forum' means..now go and search for it in your dictionary before asking here.