character change direction to follow mouse

This is my first day using Unity3D and I really enjoy it. I’m trying to make a simple game and I have a character(parent) with a camera(child) following it in 3rd person. I can control the character’s feet using W,A,S, and D, but when I hit one of these keys it will only travel in that direction. Ex. W only moves north.
I would like to be able to move my character by following the mouse direction, so when I’m holding W down and I move my mouse 45 degrees to the right, my character begins to follow.
Can anyone help me do this?

An elegant third person camera can not be achieved with such simple parenting. But you can use it to until you complete your character. I suggest you to focus on character first.

If you write down your character controller codes, someone may help you further.