I know how to change the color of the center column and how to change the color of the sidebars, but how do I change the color outside of that?

My blog is http://elizabethedwards.me, and what I want to change is the color of the area that goes from the edge of each sidebar out. For example, on this blog http://table4five.net/, there's grey on either side. I want to do that.

ato->Body, Text & Links->Body Style - background

So, do I need to create a gif image that's just the solid color I want, and upload it to wp-content/themes/atahualpa/images/ ?

Another issue that just came up - I created a new Blog Title and Tagline image in photoshop, that I want to use to replace the default title and tagline. Where does that go?

thanks!

you need to look at the CSS 'background' syntax. w3schools.com is your friend. see http://www.w3schools.com/css/css_background.asp