How do I cut out a Photo section?

Hello to all,

I am trying to learn how to cut out a section of a photo use for flash?

For an example I am trying to build a script where a user can change the color of a roof of a house. So If I take a picture how do I trace it or draw it where I can then make copies of it in different colors for people to pick a color and then make an action where the roof will change to that selected color.

Any ideas are appreciated.

Chris