customization - How to redistribute Ubuntu(Linux)?

I have Ubuntu 10.04 LTS (Ubuntu/Kubuntu and Server) and Ubuntu 12.04 LTS and Other linux distributions. I want to change its backgrounds and packages in the ISO image, so when I Install it, the modified versions are installed. And I want to redistribute the modified version.

I also want to replace the kernel with a new kernel, in the ISO.

In short, I want to customize Ubuntu (or any linux distribution) and distribute the custom version.

You can use ubuntu-builder. More information can be found on its Launchpad page:

ubuntu-builder