color change option for users

Not sure what you would call this and the example I have seen is currently off line, but I'm looking for a way for the users to change the colors of page elements to their liking. Background colors for tables and cells etc.

You would need to alter the CSS file

This is a poor example but if you read any css file you should be able to work your way in, if you need a reference try w3schools for some code reference help to alter changes.
(attribute name)
{
color:#0000;
}

It sounds like your talking about a color picker. You would use the color picker to alter the CSS styles. If that's the case unless you wanted them to set it every time they went to the page you need someway of storing that information by either a database or a cookie.